The panel devices list isn't used anymore, all panel devices are
accessed through the global devices list. Remove it.
Signed-off-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: NSebastian Reichel <sebastian.reichel@collabora.co.uk>
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>