[media] media: rcar-vin: add DV timings support

Adds ioctls DV_TIMINGS_CAP, ENUM_DV_TIMINGS, G_DV_TIMINGS, S_DV_TIMINGS,
and QUERY_DV_TIMINGS.

Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas@gmail.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>