clk: msm: clock-gcc-8996: Set core mem bit for gcc_mmss_bimc_gfx_clk

Set the FORCE_MEM_CORE_ON bit for the gcc_mmss_bimc_gfx_clk once
during clock probe on msm8996 and not toggle it for every
gdsc_gpu power cycle. This should take care of any potential
race conditions between HLOS and other entities leading to memory
corruption.

Change-Id: I10cedd16719280beabc24972e625ad8757b5e1fc
Signed-off-by: Deepak Katragadda <dkatraga@codeaurora.org>