media: v4l2-dev: Check that g/s_selection are valid before selecting crop

The cropcap and g/s_crop ioctls are automatically marked as valid whenever
the g/s_selection ops are filled. The rationale is to auto-enable these
legacy cropcap and g/s_crop ioctls that rely on g/s_selection.

However it's possible that the ops are filled but explicitly disabled with
calls to v4l2_disable_ioctl. In this situation the legacy ioctls should not
be enabled.

Add a check on the video device's valid ioctls field before auto-selecting
them to honor the driver's choice. Note that the meaning of the bitfield
stored in the video device is the opposite of what the name suggests as
v4l2_disable_ioctl will set the bits. Their meaning will be reversed at
the end of the function.

Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Reviewed-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>