media: staging: media: imx: imx7-media-csi: Replace ipu_color_space with bool yuv field

Replace the enum ipu_color_space cs field in struct imx7_csi_pixfmt with
a bool yuv field. This decouples the driver from the unrelated IPUv3
headers.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Rui Miguel Silva <rmfrfs@gmail.com>
Tested-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>