ARM: dts: da850: Add missing pin muxing for the UARTs

This adds 2 pinctrl groups (rtscts, rxtx) for each of the 3 UARTs.
Signed-off-by: Karl Beldan <kbeldan@baylibre.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>

arch/arm/boot/dts/da850.dtsi

@@ -41,6 +41,42 @@ pmx_core: pinmux@14120 {
 			pinctrl-single,function-mask = <0xf>;
 			status = "disabled";
 
+			serial0_rtscts_pins: pinmux_serial0_rtscts_pins {
+				pinctrl-single,bits = <
+					/* UART0_RTS UART0_CTS */
+					0x0c 0x22000000 0xff000000
+				>;
+			};
+			serial0_rxtx_pins: pinmux_serial0_rxtx_pins {
+				pinctrl-single,bits = <
+					/* UART0_TXD UART0_RXD */
+					0x0c 0x00220000 0x00ff0000
+				>;
+			};
+			serial1_rtscts_pins: pinmux_serial1_rtscts_pins {
+				pinctrl-single,bits = <
+					/* UART1_CTS UART1_RTS */
+					0x00 0x00440000 0x00ff0000
+				>;
+			};
+			serial1_rxtx_pins: pinmux_serial1_rxtx_pins {
+				pinctrl-single,bits = <
+					/* UART1_TXD UART1_RXD */
+					0x10 0x22000000 0xff000000
+				>;
+			};
+			serial2_rtscts_pins: pinmux_serial2_rtscts_pins {
+				pinctrl-single,bits = <
+					/* UART2_CTS UART2_RTS */
+					0x00 0x44000000 0xff000000
+				>;
+			};
+			serial2_rxtx_pins: pinmux_serial2_rxtx_pins {
+				pinctrl-single,bits = <
+					/* UART2_TXD UART2_RXD */
+					0x10 0x00220000 0x00ff0000
+				>;
+			};
 			nand_cs3_pins: pinmux_nand_pins {
 				pinctrl-single,bits = <
 					/* EMA_OE, EMA_WE */