msm: kgsl: Send NMI to GMU upon watchdog bite

Send NMI to GMU to dump CM3 system state which includes stack
being used at the time of the watchdog bite, and other key registers.
This will help record information about what instruction was executing
when the GMU watchdog bite occurred. This CM3 state is stored in both
TCM and memory, and hence will be accessible through either a snapshot
or a ramdump.

Change-Id: I396a7794ffa6391cac0b588c71d06cf357e07a2b
Signed-off-by: Sushmita Susheelendra <ssusheel@codeaurora.org>