media: rkisp1: Fix source pad format configuration

The ISP converts Bayer data to YUV when operating normally, and can also
operate in pass-through mode where the input and output formats must
match. Converting from YUV to Bayer isn't possible. If such an invalid
configuration is attempted, adjust it by copying the sink pad media bus
code to the source pad.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Dafna Hirschfeld <dafna@fastmail.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>