msm: kgsl: Allocate buffer for GMU master log

The GMU master log is allocated in uncacheable memory.
The base address of the log is communicated to the GMU
via a scratch register. This log is available for recording
events right from the start of GMU initialization.

Change-Id: I7be1ef5259101ca3fc01c042cd328ffb8d7cea39
Signed-off-by: Sushmita Susheelendra <ssusheel@codeaurora.org>
Signed-off-by: Carter Cooper <ccooper@codeaurora.org>