msm: kgsl: Cleanup some of the a6xx gpudev functions

Few functions can be handled directly without having
the gpuid checks. So cleanup these functions to avoid
unnecessary gpuid checks.

Change-Id: If5b88adb4d21d327a39dc92d657d1bf5066f6667
Signed-off-by: Hareesh Gundu <hareeshg@codeaurora.org>