media: imx: utils: Add ability to filter pixel formats by mbus code

Add a media bus code argument to the imx_media_enum_pixel_formats(). If
set to a non-zero value, the function will only consider pixel formats
that match the given media bus code.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Rui Miguel Silva <rmfrfs@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>