tools/power turbostat: Group SMI counter with APERF and MPERF

These three counters now are treated similar to other perf counters
groups. This simplifies and gets rid of a lot of special cases for APERF
and MPERF.
Signed-off-by: Patryk Wlazlyn <patryk.wlazlyn@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>