media: mtk-jpegdec: add missing destroy_workqueue()

destroy_workqueue() needs be called to when driver is
unloading, fix it by using devm_add_action_or_reset()
to make workqueuedevice-managed.

Fixes: dedc2150 ("media: mtk-jpegdec: add jpeg decode worker interface")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>