[media] v4l: subdev: Extend default link validation to cover field order

The field order must match between the source and sink pads, or the sink
pad field order must be NONE. This allows connecting an interlaced
source to a bridge that has no hardware support for interlaced formats.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Enrico Butera <ebutera@users.sourceforge.net>
Acked-by: Sakari Ailus <sakari.ailus@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>