msm: kgsl: Add handler for GPC interrupt on A6xx GPU

Add the interrupt handler to cause a snapshot when the
GPC interrupt is received for A6xx.

Change-Id: I6eabde0f2bdfc3997bf380055246c2cbdada7cdf
Signed-off-by: Carter Cooper <ccooper@codeaurora.org>
Signed-off-by: Harshdeep Dhatt <hdhatt@codeaurora.org>
Signed-off-by: Rajesh Kemisetti <rajeshk@codeaurora.org>