[media] m2m-deinterlace: Add V4L2_CAP_VIDEO_M2M capability flag

New mem-to-mem video drivers should use V4L2_CAP_VIDEO_M2M capability, rather
than ORed V4L2_CAP_VIDEO_CAPTURE and V4L2_CAP_VIDEO_OUTPUT flags, as outlined
in commit a1367f1b

.

Acked-by: Javier Martin <javier.martin@vista-silicon.com>
Signed-off-by: Sylwester Nawrocki <sylvester.nawrocki@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>