ARM: sunxi: Fix Mini X-plus device tree build

Commit b00adbe0 ("ARM: sunxi: Rename uart nodes to serial") changed the
node names in the DTSI, changes that were not accordingly made to the
Mini X-Plus device tree. This breakage slipped through because it was
not properly declared in the Makefile.

Fix both issues.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
diff --git a/arch/arm/boot/dts/sun4i-a10-mini-xplus.dts b/arch/arm/boot/dts/sun4i-a10-mini-xplus.dts
index 4a7c35d..078ed7f 100644
--- a/arch/arm/boot/dts/sun4i-a10-mini-xplus.dts
+++ b/arch/arm/boot/dts/sun4i-a10-mini-xplus.dts
@@ -22,8 +22,8 @@
 		bootargs = "earlyprintk console=ttyS0,115200";
 	};
 
-	soc {
-		uart0: uart@01c28000 {
+	soc@01c20000 {
+		uart0: serial@01c28000 {
 			pinctrl-names = "default";
 			pinctrl-0 = <&uart0_pins_a>;
 			status = "okay";