drm/rcar-du: Add internal LVDS encoder support

The R8A7790 includes two internal LVDS encoders. Support them in the DU
driver.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
diff --git a/drivers/gpu/drm/rcar-du/rcar_du_drv.c b/drivers/gpu/drm/rcar-du/rcar_du_drv.c
index 4bc3997..38a8b52 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_drv.c
+++ b/drivers/gpu/drm/rcar-du/rcar_du_drv.c
@@ -232,6 +232,7 @@
 			.encoder_type = DRM_MODE_ENCODER_NONE,
 		},
 	},
+	.num_lvds = 0,
 };
 
 static const struct rcar_du_device_info rcar_du_r8a7790_info = {
@@ -255,6 +256,7 @@
 			.encoder_type = DRM_MODE_ENCODER_LVDS,
 		},
 	},
+	.num_lvds = 2,
 };
 
 static const struct platform_device_id rcar_du_id_table[] = {