media: staging: rkisp1: add serialization to the isp subdev ops

media: staging: rkisp1: add serialization to the isp subdev ops

For subdevices drivers, the drivers themself are responsible
for serializing their operations.
This patch adds serialization to the isp subdevice.

Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
Acked-by: Helen Koike <helen.koike@collabora.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>