staging: imx-drm: add missing MFD_SYSCON dependency for LDB

Added missing MFD_SYSCON dependency for LVDS display bridge
in order to fix the following link error.

drivers/staging/imx-drm/imx-ldb.c:484: undefined reference to `syscon_regmap_lookup_by_phandle'
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Acked-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/imx-drm/Kconfig

@@ -32,7 +32,7 @@ config DRM_IMX_TVE
 
 config DRM_IMX_LDB
 	tristate "Support for LVDS displays"
-	depends on DRM_IMX
+	depends on DRM_IMX && MFD_SYSCON
 	help
 	  Choose this to enable the internal LVDS Display Bridge (LDB)
 	  found on i.MX53 and i.MX6 processors.