tools/power turbostat: stop migrating, unless '-m'

Turbostat has the capability to set its own affinity to
each CPU so that its MSR accesses are on the local CPU.

However, using the in-kernel cross-call in  the msr driver
tends to be less invasive, so do that -- by-default.
'-m' remains to get the old behaviour.

Signed-off-by: Len Brown <len.brown@intel.com>