tools/power turbostat: use new MSR_TURBO_RATIO_LIMIT names

s/MSR_NHM_TURBO_RATIO_LIMIT/MSR_TURBO_RATIO_LIMIT/
s/MSR_IVT_TURBO_RATIO_LIMIT/MSR_TURBO_RATIO_LIMIT1/

syntax only -- use the documented strings describing these registers.

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