ARM: dts: sun9i: Add pinmux setting for mmc0

mmc0 is only available on port F, and is always used with a 4 bit wide
bus for the onboard micro-sd slot.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

arch/arm/boot/dts/sun9i-a80.dtsi

@@ -409,6 +409,14 @@ i2c3_pins_a: i2c3@0 {
 				allwinner,pull = <SUN4I_PINCTRL_NO_PULL>;
 			};
 
+			mmc0_pins: mmc0 {
+				allwinner,pins = "PF0", "PF1" ,"PF2", "PF3",
+						 "PF4", "PF5";
+				allwinner,function = "mmc0";
+				allwinner,drive = <SUN4I_PINCTRL_30_MA>;
+				allwinner,pull = <SUN4I_PINCTRL_NO_PULL>;
+			};
+
 			uart0_pins_a: uart0@0 {
 				allwinner,pins = "PH12", "PH13";
 				allwinner,function = "uart0";