A failure to locate the external subdev for a non memory-to-memory
pipeline is a fatal error, don't ignore it.
Signed-off-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: NSakari Ailus <sakari.ailus@iki.fi>
Tested-by: NPeter Meerwald <pmeerw@pmeerw.net>
Signed-off-by: NMauro Carvalho Chehab <m.chehab@samsung.com>