media: remove soc_camera ov9640

This driver got converted to not depend on soc_camera on commit
57b0ad9e ("media: soc_camera: ov9640: move ov9640 out of soc_camera").

There's no sense on keeping the old version there.

Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Acked-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>