drm/panfrost: Handle job HW submit errors

drm/panfrost: Handle job HW submit errors

Avoid waiting for the DRM scheduler job timedout handler, and instead, let
the DRM scheduler core signal the error fence immediately when HW job
submission fails.

That means we must also decrement the runtime-PM refcnt for the device,
because the job will never be enqueued or inflight.

Reviewed-by: Steven Price <steven.price@arm.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Adrián Larumbe <adrian.larumbe@collabora.com>
Link: https://lore.kernel.org/r/20251019145225.3621989-4-adrian.larumbe@collabora.com
Signed-off-by: Steven Price <steven.price@arm.com>