msm: npu: handle system shutdown/reboot event properly

When system shuts down while there are work running on NPU,
NPUSS will be shut down without notifying kernel driver which
causes IPC commands timedout and triggers SSR handling.
This change is to detect this case and handle it properly
to avoid SSR.

Change-Id: Ieb0f8f877b0eb6f615083cb824ec859c369a2701
Signed-off-by: Shaoqi,Li <quic_shaoli@quicinc.com>