msm: kgsl: Disable memory retention for core clock before entering SLUMBER

Memory retention is needed only for NAP state but not for SLUMBER state.
Disables memory retention for core clock before entering SLUMBER to save
power.

Change-Id: I64a5ecec6fc90d662da8d9d793860e56b0c6473f
Signed-off-by: Deepak Kumar <dkumar@codeaurora.org>
5 files changed