drm/imx: imx-ldb: remove useless enum

Since commit 5e501ed7 ("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>

drivers/gpu/drm/imx/imx-ldb.c

@@ -464,11 +464,6 @@ static int imx_ldb_register(struct drm_device *drm,
 	return 0;
 }
 
-enum {
-	LVDS_BIT_MAP_SPWG,
-	LVDS_BIT_MAP_JEIDA
-};
-
 struct imx_ldb_bit_mapping {
 	u32 bus_format;
 	u32 datawidth;