soc: qcom: Manage multipe clusters at a time in msm_perf module

Adding support to manage multiple clusters at a time in
msm_performance driver. The number of clusters and the respective
masks are initialized once from userspace and then the max_cpus
tunable can be used to manage the CPUs to be put online in the
cluster thereafter.

Change-Id: I35a80af37e1ecedbc53670edd65698170fe349e1
Signed-off-by: Rohit Gupta <rohgup@codeaurora.org>