clk: msm: clock-gcc: Add support to toggle MEM_CORE/PERIPH bits

The mem_core and mem_periph bits are required to be toggle when the branch
clock is enabled and disabled thus helping in saving any power due to these
bits being left on.

Change-Id: I0bc4080c265ce2b4700c91d0e8e441dcf60ab903
Signed-off-by: Taniya Das <tdas@codeaurora.org>