dts/imx: rename uart labels to consistent with hw spec

UART1/UART2/... is more readable than UART0/UART1/... .
Remove redundant UART comments.

Signed-off-by: Richard Zhao <richard.zhao@linaro.org>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
diff --git a/arch/arm/boot/dts/imx51.dtsi b/arch/arm/boot/dts/imx51.dtsi
index 57a790d..6663986 100644
--- a/arch/arm/boot/dts/imx51.dtsi
+++ b/arch/arm/boot/dts/imx51.dtsi
@@ -14,9 +14,9 @@
 
 / {
 	aliases {
-		serial0 = &uart0;
-		serial1 = &uart1;
-		serial2 = &uart2;
+		serial0 = &uart1;
+		serial1 = &uart2;
+		serial2 = &uart3;
 	};
 
 	tzic: tz-interrupt-controller@e0000000 {
@@ -86,7 +86,7 @@
 					status = "disabled";
 				};
 
-				uart2: uart@7000c000 { /* UART3 */
+				uart3: uart@7000c000 {
 					compatible = "fsl,imx51-uart", "fsl,imx21-uart";
 					reg = <0x7000c000 0x4000>;
 					interrupts = <33>;
@@ -171,14 +171,14 @@
 				status = "disabled";
 			};
 
-			uart0: uart@73fbc000 {
+			uart1: uart@73fbc000 {
 				compatible = "fsl,imx51-uart", "fsl,imx21-uart";
 				reg = <0x73fbc000 0x4000>;
 				interrupts = <31>;
 				status = "disabled";
 			};
 
-			uart1: uart@73fc0000 {
+			uart2: uart@73fc0000 {
 				compatible = "fsl,imx51-uart", "fsl,imx21-uart";
 				reg = <0x73fc0000 0x4000>;
 				interrupts = <32>;