cpu Mhz with current, max and min.

[alexwbaule]

Is your feature request related to a problem? Please describe.
psutils from python, mas current, max and min.

Describe the solution you'd like
extend "Mhz" struct, with this 3 values.

Describe alternatives you've considered
Extend the InfoStat like this.

type InfoStat struct {
	CPU        int32    `json:"cpu"`
	VendorID   string   `json:"vendorId"`
	Family     string   `json:"family"`
	Model      string   `json:"model"`
	Stepping   int32    `json:"stepping"`
	PhysicalID string   `json:"physicalId"`
	CoreID     string   `json:"coreId"`
	Cores      int32    `json:"cores"`
	ModelName  string   `json:"modelName"`
	Mhz        Mhz      `json:"mhz"`
	CacheSize  int32    `json:"cacheSize"`
	Flags      []string `json:"flags"`
	Microcode  string   `json:"microcode"`
}

type Mhz struct {
      current      float64  `json:"current"` //from cpuinfo or cpufreq/cpuinfo_cur_freq 
      max          float64  `json:"max"` //from cpufreq/cpuinfo_max_freq 
      min          float64  `json:"min"`  //from cpufreq/cpuinfo_min_freq 
}

Additional context
If i can do a PR, i do. The only problem, is that i only has linux to test.