drm/imx: Add missing DRM_FORMAT_RGB565 to ipu_plane_formats

DRM_FORMAT_RGB565 is missing from ipu_plane_formats.
The support is there, just need to make it available to userspace.

Signed-off-by: Enrico Jorns <ejo@pengutronix.de>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
diff --git a/drivers/gpu/drm/imx/ipuv3-plane.c b/drivers/gpu/drm/imx/ipuv3-plane.c
index 591ba2f..26bb1b6 100644
--- a/drivers/gpu/drm/imx/ipuv3-plane.c
+++ b/drivers/gpu/drm/imx/ipuv3-plane.c
@@ -42,6 +42,7 @@
 	DRM_FORMAT_YVYU,
 	DRM_FORMAT_YUV420,
 	DRM_FORMAT_YVU420,
+	DRM_FORMAT_RGB565,
 };
 
 int ipu_plane_irq(struct ipu_plane *ipu_plane)