media: staging: rkisp1: cap: enable RGB capture format with YUV media bus

In selfpath, RGB capture formats are received in the sink pad as YUV
and are converted to RGB only when writing to memory. So the validation
function should accept YUV bus formats with RGB capture encoding.

Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>