features: Fix test TestHaveProgramType/Extension in kernel >=v6.8

In kernel v6.8, logic was added that restricts valid func info BTF for
programs that can be replaced with an BPF_PROG_TYPE_EXT program.
Before this change the parameters of the extension program had to be
the same as the original program. However, now the verifier asserts
that the BTF func info of "main" programs must have exactly 1 parameter
of a pointer type to the context struct, even if the code doesn't use
the context like in our case.

Signed-off-by: Dylan Reimerink <dylan.reimerink@isovalent.com>

features/prog.go

@@ -125,6 +125,9 @@ var haveProgramTypeMatrix = internal.FeatureMatrix[ebpf.ProgramType]{
 				Name: "a",
 				Type: &btf.FuncProto{
 					Return: &btf.Int{},
+					Params: []btf.FuncParam{
+						{Name: "ctx", Type: &btf.Pointer{Target: &btf.Struct{Name: "xdp_md"}}},
+					},
 				},
 				Linkage: btf.GlobalFunc,
 			}