msm: rq_stats: Use cpufreq API to get the current frequency

Since the acpuclock APIs are deprecated, use the cpufreq to
get the current frequency of CPUs to calculate the cpu
normalized load value.

Change-Id: I6e381d584d6725ef964bad86c835d44f3046e9c3
Signed-off-by: Archana Sathyakumar <asathyak@codeaurora.org>