media: MAINTAINERS: remove SOC-CAMERA entry

After the removal of the soc_camera driver and the soc_camera.h header
the SOC-CAMERA entry in the MAINTAINERS file can also be removed.

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