[media] rcar-vin: move chip check for pixelformat support

The check for if the specific pixelformat is supported on the current
chip should happen in VIDIOC_S_FMT and VIDIOC_TRY_FMT and not when we
try to setup the hardware for streaming.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>