drm/rcar-du: Handle encoder initialization failures

The rcar_du_encoder_init() function can fail and return an error code.
Don't ignore it.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/rcar-du/rcar_du_kms.c

@@ -248,7 +248,10 @@ int rcar_du_modeset_init(struct rcar_du_device *rcdu)
 			continue;
 		}
 
-		rcar_du_encoder_init(rcdu, pdata->type, pdata->output, pdata);
+		ret = rcar_du_encoder_init(rcdu, pdata->type, pdata->output,
+					   pdata);
+		if (ret < 0)
+			return ret;
 	}
 
 	/* Set the possible CRTCs and possible clones. There's always at least