msm: kgsl: Clear boot OOB in case GPU start fails

Clear the boot OOB, if GPU start fails after successfully
changing KGSL state to AWARE. This is needed to make sure
GMU stop sequence works fine and recovery can happen.

Change-Id: I98832da9dea429cac3104a859e0d6e6091d959a5
Signed-off-by: Deepak Kumar <dkumar@codeaurora.org>