msm: kgsl: Do not send NMI to GMU on CM3 fault

Say GMU hits a hard fault and saves critical debug state and
sends CM3 fault interrupt. It is possible that subsequent handshake
between kgsl and GMU will timeout and kgsl will trigger GMU snapshot.
This will send an NMI to GMU, which will over-write the critical debug
state. To avoid this, check if there was a CM3 fault before sending
NMI to the GMU.

Change-Id: I0d4d4af3efe31110123f614c8dd8fe8d4a04c812
Signed-off-by: Harshdeep Dhatt <hdhatt@codeaurora.org>