Fix cpu stats when hw.smt is enabled
Fix cpu stats when hw.smt is enabled

When hw.smt is enabled, and it's enabled by default from 6.4, the
number of cpus given by `runtime.NumCPU()` is half of the total: only
the cpuN with N = 0,2,4,... are used by the system. We need to detect
that and ask for the correct stats.

influxdb/gopsutil,influxdb/gopsutil