gpio: sunxi: Add compatible string for R40 PIO

The PIO on the R40 SoC is mostly compatible with the A20.
Only a few pin functions for mmc2 were added to the PC
pingroup, to support 8 bit eMMCs.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>

drivers/gpio/sunxi_gpio.c

@@ -352,6 +352,7 @@ static const struct udevice_id sunxi_gpio_ids[] = {
 	ID("allwinner,sun8i-a33-pinctrl",	a_all),
 	ID("allwinner,sun8i-a83t-pinctrl",	a_all),
 	ID("allwinner,sun8i-h3-pinctrl",	a_all),
+	ID("allwinner,sun8i-r40-pinctrl",	a_all),
 	ID("allwinner,sun9i-a80-pinctrl",	a_all),
 	ID("allwinner,sun6i-a31-r-pinctrl",	l_2),
 	ID("allwinner,sun8i-a23-r-pinctrl",	l_1),