Fix node stats updates on Windows (#1748)

Because we aren't able to get CPU count/load info on Windows, they are
stubbed out to return placeholders. This restores compatibility to run
on Windows.

pkg/telemetry/prometheus/node_linux.go

@@ -5,37 +5,10 @@ package prometheus
 
 import (
 	"fmt"
-	"sync"
 
 	"github.com/florianl/go-tc"
-	"github.com/mackerelio/go-osstat/cpu"
 )
 
-var (
-	cpuStatsLock              sync.RWMutex
-	lastCPUTotal, lastCPUIdle uint64
-)
-
-func getCPUStats() (cpuLoad float32, numCPUs uint32, err error) {
-	cpuInfo, err := cpu.Get()
-	if err != nil {
-		return
-	}
-
-	cpuStatsLock.Lock()
-	if lastCPUTotal > 0 && lastCPUTotal < cpuInfo.Total {
-		cpuLoad = 1 - float32(cpuInfo.Idle-lastCPUIdle)/float32(cpuInfo.Total-lastCPUTotal)
-	}
-
-	lastCPUTotal = cpuInfo.Total
-	lastCPUIdle = cpuInfo.Idle // + cpu.Iowait
-	cpuStatsLock.Unlock()
-
-	numCPUs = uint32(cpuInfo.CPUCount)
-
-	return
-}
-
 func getTCStats() (packets, drops uint32, err error) {
 	rtnl, err := tc.Open(&tc.Config{})
 	if err != nil {