media: driver: s3c_camif: move s3c_camif_unregister_subdev out of camif_unregister_media_entities

In the error handling of s3c_camif_probe, s3c_camif_unregister_subdev
may be executed twice, one is from camif_unregister_media_entities.
Although there is sanity check about the registration status,
it is not good to call s3c_camif_unregister_subdev twice in the error
handling code.

Fix this by moving s3c_camif_unregister_subdev out of
camif_unregister_media_entities, and add a s3c_camif_unregister_subdev
in the s3c_camif_remove.

Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>