ARM: mx28: add auart4 2 pins pinmux to imx28.dtsi

Add auart4 2 pins configuration on SSP3 pads
Signed-off-by: Eric Bénard <eric@eukrea.com>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>

arch/arm/boot/dts/imx28.dtsi

@@ -376,6 +376,17 @@ auart3_2pins_b: auart3-2pins@1 {
 					fsl,pull-up = <0>;
 				};
 
+				auart4_2pins_a: auart4@0 {
+					reg = <0>;
+					fsl,pinmux-ids = <
+						0x2181 /* MX28_PAD_SSP3_SCK__AUART4_TX */
+						0x2191 /* MX28_PAD_SSP3_MOSI__AUART4_RX */
+					>;
+					fsl,drive-strength = <0>;
+					fsl,voltage = <1>;
+					fsl,pull-up = <0>;
+				};
+
 				mac0_pins_a: mac0@0 {
 					reg = <0>;
 					fsl,pinmux-ids = <