drm/panfrost: Reset the GPU when the AS_ACTIVE bit is stuck

Things are unlikely to resolve until we reset the GPU. Let's not wait
for other faults/timeout to happen to trigger this reset.

Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210630062751.2832545-13-boris.brezillon@collabora.com