msm: kgsl: Add 8974 default GPR0 & clk gating values

Add correct clock gating values for A330, A305 and A320.
Add generic function to return the correct default clock
gating values for the respective gpu. Add default GPR0
value for A330.

Change-Id: I039e8e3622cbda04924b0510e410a9dc95bec598
Signed-off-by: Harsh Vardhan Dwivedi <hdwivedi@codeaurora.org>