drm/sun4i: frontend: Hook-in support for the A20

This adds the appropriate device-tree compatible for hooking frontend
support for the A20. Since the hardware is very similar to the A10, it
shares the same quirks (which were already introduced).

Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190118145133.21281-24-paul.kocialkowski@bootlin.com

drivers/gpu/drm/sun4i/sun4i_frontend.c

@@ -715,6 +715,10 @@ const struct of_device_id sun4i_frontend_of_table[] = {
 		.compatible = "allwinner,sun4i-a10-display-frontend",
 		.data = &sun4i_a10_frontend
 	},
+	{
+		.compatible = "allwinner,sun7i-a20-display-frontend",
+		.data = &sun4i_a10_frontend
+	},
 	{
 		.compatible = "allwinner,sun8i-a33-display-frontend",
 		.data = &sun8i_a33_frontend