msm: msm_bus: Fix a warning by correcting mem-clock usage

Till now mem-clocks were supported only in active context.
Due to that a potential out-of-bounds array access was
caught, which would result in a mem-clock access in sleep
context. Fix this by adding support for mem-clock in active
and sleep context.

Change-Id: I8772621cd20821cccf0d187fc1fb688fe8fda76e
Signed-off-by: Gagan Mac <gmac@codeaurora.org>