ARM: sun5i: dt: Add i2c muxing options

The i2c controller found on the Allwinner A13 has only one muxing option
available for each controller. Add them to the dtsi

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Reviewed-by: Tomasz Figa <tomasz.figa@gmail.com>

arch/arm/boot/dts/sun5i-a13.dtsi

@@ -184,6 +184,27 @@
 				allwinner,drive = <0>;
 				allwinner,pull = <0>;
 			};
+
+			i2c0_pins_a: i2c0@0 {
+				allwinner,pins = "PB0", "PB1";
+				allwinner,function = "i2c0";
+				allwinner,drive = <0>;
+				allwinner,pull = <0>;
+			};
+
+			i2c1_pins_a: i2c1@0 {
+				allwinner,pins = "PB15", "PB16";
+				allwinner,function = "i2c1";
+				allwinner,drive = <0>;
+				allwinner,pull = <0>;
+			};
+
+			i2c2_pins_a: i2c2@0 {
+				allwinner,pins = "PB17", "PB18";
+				allwinner,function = "i2c2";
+				allwinner,drive = <0>;
+				allwinner,pull = <0>;
+			};
 		};
 
 		timer@01c20c00 {