media: imx: capture: Move default format init to a separate function
To prepare for more complex default format initialization and keep
imx_media_capture_device_register() simple, extract the format
initialization code to a separate function.
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>