msm: kgsl: Reorganize interrupt management code

Interrupts are specific to GPU core, even though some interrupt
lines are common between axxx cores it is cleaner to define and
manage interrupts for each core separately. There is some code
duplication but it is minimal.

Move common functions in axxx cores to adreno.c/h files.
Move adreno_axxx_pending/control/handler/setup functions to adreno.c,
these functions do not need to be in adreno_axxx.c files.

Change-Id: Ie5b780cd3fb5313c6055d723fc2d00f4e0895c1f
Signed-off-by: Tarun Karra <tkarra@codeaurora.org>