drm/scheduler: Don't kill jobs in interrupt context

Interrupt context can't sleep. Drivers like Panfrost and MSM are taking
mutex when job is released, and thus, that code can sleep. This results
into "BUG: scheduling while atomic" if locks are contented while job is
freed. There is no good reason for releasing scheduler's jobs in IRQ
context, hence use normal context to fix the trouble.

Reviewed-by: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Tested-by: Erico Nunes <nunes.erico@gmail.com>
Cc: stable@vger.kernel.org
Fixes: 542cff78 ("drm/sched: Avoid lockdep spalt on killing a processes")
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>