msm: kgsl: Do not detect faults when GPU core is idle

Do not detect GPU faults when GPU hardware status is idle,
this leads to incorrect fault detection.

Signed-off-by: Tarun Karra <tkarra@codeaurora.org>
Signed-off-by: Hareesh Gundu <hareeshg@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>