CPU core count is wrong

[Forza-tng]

I noticed that p7zip is not reading the CPU core count properly on my AMD system.

I have a 6c/12t Ryzen 5600G, but p7zip is thinking it has 32 CPUs, which is current maximum supported in my kernel (CONFIG_NR_CPUS=32).

# 7z b
7-Zip [64] 17.05 : Copyright (c) 1999-2021 Igor Pavlov : 2017-08-28
p7zip Version 17.05 (locale=en_GB.utf8,Utf16=on,HugeFiles=on,64 bits,32 CPUs AMD Ryzen 5 5600G with Radeon Graphics          (A50F00),ASM,AES-NI)

AMD Ryzen 5 5600G with Radeon Graphics          (A50F00)
CPU Freq: - - - - - - - - -

RAM size:   31463 MB,  # CPU hardware threads:  32
RAM usage:   7060 MB,  # Benchmark threads:     32

                       Compressing  |                  Decompressing
Dict     Speed Usage    R/U Rating  |      Speed Usage    R/U Rating
         KiB/s     %   MIPS   MIPS  |      KiB/s     %   MIPS   MIPS

22:      50807  1179   4190  49425  |     567636  1159   4177  48407
23:      47798  1171   4157  48701  |     560030  1165   4159  48460
24:      45851  1177   4189  49300  |     546826  1167   4114  47997
25:      43173  1164   4236  49293  |     530928  1161   4069  47249
----------------------------------  | ------------------------------
Avr:            1173   4193  49180  |             1163   4130  48028
Tot:            1168   4161  48604

# lscpu
Architecture:                         x86_64
CPU op-mode(s):                       32-bit, 64-bit
Address sizes:                        48 bits physical, 48 bits virtual
Byte Order:                           Little Endian
CPU(s):                               12
On-line CPU(s) list:                  0-11
Vendor ID:                            AuthenticAMD
BIOS Vendor ID:                       Advanced Micro Devices, Inc.
Model name:                           AMD Ryzen 5 5600G with Radeon Graphics
BIOS Model name:                      AMD Ryzen 5 5600G with Radeon Graphics          Unknown CPU @ 3.9GHz
BIOS CPU family:                      107
CPU family:                           25
Model:                                80
Thread(s) per core:                   2
Core(s) per socket:                   6
Socket(s):                            1
Stepping:                             0
BogoMIPS:                             7785,29
Flags:                                fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt pdpe1gb rdtscp lm constant_tsc rep_good nopl nonstop_tsc cpuid extd_apicid aperfmperf rapl pni pclmulqdq monitor ssse3 fma cx16 sse4_1 sse4_2 x2apic movbe popcnt aes xsave avx f16c rdrand lahf_lm cmp_legacy svm extapic cr8_legacy abm sse4a misalignsse 3dnowprefetch osvw ibs skinit wdt tce topoext perfctr_core perfctr_nb bpext perfctr_llc mwaitx cpb cat_l3 cdp_l3 hw_pstate ssbd mba ibrs ibpb stibp vmmcall fsgsbase bmi1 avx2 smep bmi2 erms invpcid cqm rdt_a rdseed adx smap clflushopt clwb sha_ni xsaveopt xsavec xgetbv1 xsaves cqm_llc cqm_occup_llc cqm_mbm_total cqm_mbm_local user_shstk clzero irperf xsaveerptr rdpru wbnoinvd cppc arat npt lbrv svm_lock nrip_save tsc_scale vmcb_clean flushbyasid decodeassists pausefilter pfthreshold avic v_vmsave_vmload vgif v_spec_ctrl umip pku ospke vaes vpclmulqdq rdpid overflow_recov succor smca fsrm debug_swap
Virtualization:                       AMD-V
L1d cache:                            192 KiB (6 instances)
L1i cache:                            192 KiB (6 instances)
L2 cache:                             3 MiB (6 instances)
L3 cache:                             16 MiB (1 instance)
NUMA node(s):                         1
NUMA node0 CPU(s):                    0-11
Vulnerability Gather data sampling:   Not affected
Vulnerability Itlb multihit:          Not affected
Vulnerability L1tf:                   Not affected
Vulnerability Mds:                    Not affected
Vulnerability Meltdown:               Not affected
Vulnerability Mmio stale data:        Not affected
Vulnerability Reg file data sampling: Not affected
Vulnerability Retbleed:               Not affected
Vulnerability Spec rstack overflow:   Mitigation; Safe RET
Vulnerability Spec store bypass:      Mitigation; Speculative Store Bypass disabled via prctl
Vulnerability Spectre v1:             Mitigation; usercopy/swapgs barriers and __user pointer sanitization
Vulnerability Spectre v2:             Mitigation; Retpolines, IBPB conditional, IBRS_FW, STIBP always-on, RSB filling, PBRSB-eIBRS Not affected
Vulnerability Srbds:                  Not affected
Vulnerability Tsx async abort:        Not affected

# getconf -a | grep PROCESSORS
_NPROCESSORS_CONF                  32
_NPROCESSORS_ONLN                  12