[media] adv7604: Receive CEA formats as RGB on VGA (RGB) input

If the input is ADV7604_INPUT_VGA_RGB and RGB quantization range is
set to V4L2_DV_RGB_RANGE_AUTO, video with CEA timings will be
received as RGB. For ADV7604_INPUT_VGA_COMP, automatic CSC mode
will be selected.

See table 44 on page 205 in "ADV7604 Hardware Manual, Rev. F, August 2010"
for details.

Signed-off-by: Mats Randgaard <matrandg@cisco.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>