media: sun6i: Add A31 compatible

The first device that used that IP was the A31. Add it to our list of
compatibles.
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Reviewed-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/media/platform/sunxi/sun6i-csi/sun6i_csi.c

@@ -892,6 +892,7 @@ static int sun6i_csi_remove(struct platform_device *pdev)
 }
 
 static const struct of_device_id sun6i_csi_of_match[] = {
+	{ .compatible = "allwinner,sun6i-a31-csi", },
 	{ .compatible = "allwinner,sun8i-v3s-csi", },
 	{},
 };