msm: kgsl: Regroup the A3XX registers as per the GPU blocks

Regroup the A3XX registers based on the GPU block
they belongs to. It is for better code readability
and understanding in GPU snapshot dump.

Change-Id: I7c0d27cb5f866f0015f827570c6912d133f60aa8
Signed-off-by: Sunil Khatri <sunilkh@codeaurora.org>