ARM: dts: sun8i: h3: Enable AP6212 BT on uart3 on Nanopi M1 Plus

The BT side of the AP6212 WiFi/BT combo module is connected to
uart3.

Enable BT on this board by enabling uart3 with using additionally
the cts and rts pins.
Signed-off-by: Philipp Rossak <embed3d@gmail.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

arch/arm/boot/dts/sun8i-h3-nanopi-m1-plus.dts

@@ -45,6 +45,10 @@
 / {
 	model = "FriendlyArm NanoPi M1 Plus";
 	compatible = "friendlyarm,nanopi-m1-plus", "allwinner,sun8i-h3";
+
+	aliases {
+		serial1 = &uart3;
+	};
 };
 
 &ehci1 {
@@ -68,3 +72,9 @@ &ohci1 {
 &ohci2 {
 	status = "okay";
 };
+
+&uart3 {
+	pinctrl-names = "default";
+	pinctrl-0 = <&uart3_pins>, <&uart3_rts_cts_pins>;
+	status = "okay";
+};