soc: qcom: msm_perf: fix invalid usuage of cpumask

set/get API used for freq updates are using an invalid cpumask
variables which may potentially lead to stack corruption.

Change-Id: I25fdc5dc25550c39bc81a2efbd55d16679d37e19
Signed-off-by: Kishore Sri venkata Ganesh Bolisetty <bsrivenk@codeaurora.org>