LVDS and RGB interfaces are always connected to TCONs which have channel
0. It doesn't make sense to try to init them on TV TCONs.

Add a check if TCON has channel 0 before trying to init LVDS or RGB
interface.
Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180625120304.7543-12-jernej.skrabec@siol.net