msm: rpm_log: Fix bugs on ring buffer reads
msm: rpm_log: Fix bugs on ring buffer reads

Incorrect right shift and improper update to tail index
reads wrong raw data from RPM RAM occasionally. Modify
rpm log to fix wrong reads of raw data on 8960.

Change-Id: I0d8bdeb8825849635ffc4173ecacbe92aca3c87b
Signed-off-by: Priyanka Mathur <505f6013be60e22c127e7e36a868fea1cf3acc88@codeaurora.org>

TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas