[media] media: rcar_vin: Reject videobufs that are too small for current format

In videobuf_setup reject buffers that are too small for the configured
format. Fixes v4l2-compliance issue.

Signed-off-by: Rob Taylor <rob.taylor@codethink.co.uk>
Reviewed-by: William Towle <william.towle@codethink.co.uk>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>