Since commit 5e501ed7253b ("drm/imx: imx-ldb: allow to determine bus
format from the connected panel") the enum isn't used anymore. Drop it
to cleanup the code a bit.
Signed-off-by: Marco Felsch <m.felsch@pengutronix.de> Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>