arm64: allwinner: a64: Add MMC pinctrl nodes

The A64 only has a single set of pins for each MMC controller. Since we
already have boards that require all of them, let's add them to the DTSI.
Reviewed-by: NAndre Przywara <andre.przywara@arm.com>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>
Tested-by: NFlorian Vaussard <florian.vaussard@heig-vd.ch>
Acked-by: NChen-Yu Tsai <wens@csie.org>

arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi

@@ -243,6 +243,31 @@
 				function = "i2c1";
 			};
 
+			mmc0_pins: mmc0-pins {
+				pins = "PF0", "PF1", "PF2", "PF3",
+				       "PF4", "PF5";
+				function = "mmc0";
+				drive-strength = <30>;
+				bias-pull-up;
+			};
+
+			mmc1_pins: mmc1-pins {
+				pins = "PG0", "PG1", "PG2", "PG3",
+				       "PG4", "PG5";
+				function = "mmc1";
+				drive-strength = <30>;
+				bias-pull-up;
+			};
+
+			mmc2_pins: mmc2-pins {
+				pins = "PC1", "PC5", "PC6", "PC8", "PC9",
+				       "PC10","PC11", "PC12", "PC13",
+				       "PC14", "PC15", "PC16";
+				function = "mmc2";
+				drive-strength = <30>;
+				bias-pull-up;
+			};
+
 			uart0_pins_a: uart0@0 {
 				pins = "PB8", "PB9";
 				function = "uart0";