msm: thermal: Add support to do optimized cluster mitigation in KTM

Add support in KTM to optimize the frequency mitigation on a
synchronous cluster based devices. KTM now gets the frequency
plan for all the clusters and mitigates the clusters based on
the cluster's frequency plan. For synchronous clusters, KTM
now aggregates the frequency requests for individual cores
in that cluster and applies that aggregated frequency to a
single online core in that cluster, thus optimizing the number
of cpu frequency update calls. The cpufreq driver will take
care of updating the rest of the sibling cores in that cluster.

KTM also supports devices with asynchronous cores in a cluster
and it is backward compatible with devices having no cluster
based architecture.

Change-Id: Ic1f5516dd6c4b6b5bc48179ec88d5d34dee19cf8
Signed-off-by: Ram Chandrasekar <rkumbako@codeaurora.org>