ARM64: dts: meson-axg: uart: Add the pinctrl info description

Describe the pinctrl info for the UART controller which is found
in the Meson-AXG SoCs.
Signed-off-by: Yixun Lan <yixun.lan@amlogic.com>
[khilman: s/uart_ao_b_gpioz/uart_ao_b_z/ ]
Signed-off-by: Kevin Hilman <khilman@baylibre.com>

arch/arm64/boot/dts/amlogic/meson-axg.dtsi

@@ -597,6 +597,70 @@ mux {
 						function = "i2c3";
 					};
 				};
+
+				uart_a_pins: uart_a {
+					mux {
+						groups = "uart_tx_a",
+							"uart_rx_a";
+						function = "uart_a";
+					};
+				};
+
+				uart_a_cts_rts_pins: uart_a_cts_rts {
+					mux {
+						groups = "uart_cts_a",
+							"uart_rts_a";
+						function = "uart_a";
+					};
+				};
+
+				uart_b_x_pins: uart_b_x {
+					mux {
+						groups = "uart_tx_b_x",
+							"uart_rx_b_x";
+						function = "uart_b";
+					};
+				};
+
+				uart_b_x_cts_rts_pins: uart_b_x_cts_rts {
+					mux {
+						groups = "uart_cts_b_x",
+							"uart_rts_b_x";
+						function = "uart_b";
+					};
+				};
+
+				uart_b_z_pins: uart_b_z {
+					mux {
+						groups = "uart_tx_b_z",
+							"uart_rx_b_z";
+						function = "uart_b";
+					};
+				};
+
+				uart_b_z_cts_rts_pins: uart_b_z_cts_rts {
+					mux {
+						groups = "uart_cts_b_z",
+							"uart_rts_b_z";
+						function = "uart_b";
+					};
+				};
+
+				uart_ao_b_z_pins: uart_ao_b_z {
+					mux {
+						groups = "uart_ao_tx_b_z",
+							"uart_ao_rx_b_z";
+						function = "uart_ao_b_z";
+					};
+				};
+
+				uart_ao_b_z_cts_rts_pins: uart_ao_b_z_cts_rts {
+					mux {
+						groups = "uart_ao_cts_b_z",
+							"uart_ao_rts_b_z";
+						function = "uart_ao_b_z";
+					};
+				};
 			};
 		};
 
@@ -647,6 +711,38 @@ mux {
 						function = "remote_input_ao";
 					};
 				};
+
+				uart_ao_a_pins: uart_ao_a {
+					mux {
+						groups = "uart_ao_tx_a",
+							"uart_ao_rx_a";
+						function = "uart_ao_a";
+					};
+				};
+
+				uart_ao_a_cts_rts_pins: uart_ao_a_cts_rts {
+					mux {
+						groups = "uart_ao_cts_a",
+							"uart_ao_rts_a";
+						function = "uart_ao_a";
+					};
+				};
+
+				uart_ao_b_pins: uart_ao_b {
+					mux {
+						groups = "uart_ao_tx_b",
+							"uart_ao_rx_b";
+						function = "uart_ao_b";
+					};
+				};
+
+				uart_ao_b_cts_rts_pins: uart_ao_b_cts_rts {
+					mux {
+						groups = "uart_ao_cts_b",
+							"uart_ao_rts_b";
+						function = "uart_ao_b";
+					};
+				};
 			};
 
 			pwm_AO_ab: pwm@7000 {