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

GPIO1/GPIO2/... is more readable than GPIO0/GPIO1/... .
Remove redundant gpio 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 327ab8e..57a790d 100644
--- a/arch/arm/boot/dts/imx51.dtsi
+++ b/arch/arm/boot/dts/imx51.dtsi
@@ -117,7 +117,7 @@
 				};
 			};
 
-			gpio0: gpio@73f84000 { /* GPIO1 */
+			gpio1: gpio@73f84000 {
 				compatible = "fsl,imx51-gpio", "fsl,imx31-gpio";
 				reg = <0x73f84000 0x4000>;
 				interrupts = <50 51>;
@@ -127,7 +127,7 @@
 				#interrupt-cells = <1>;
 			};
 
-			gpio1: gpio@73f88000 { /* GPIO2 */
+			gpio2: gpio@73f88000 {
 				compatible = "fsl,imx51-gpio", "fsl,imx31-gpio";
 				reg = <0x73f88000 0x4000>;
 				interrupts = <52 53>;
@@ -137,7 +137,7 @@
 				#interrupt-cells = <1>;
 			};
 
-			gpio2: gpio@73f8c000 { /* GPIO3 */
+			gpio3: gpio@73f8c000 {
 				compatible = "fsl,imx51-gpio", "fsl,imx31-gpio";
 				reg = <0x73f8c000 0x4000>;
 				interrupts = <54 55>;
@@ -147,7 +147,7 @@
 				#interrupt-cells = <1>;
 			};
 
-			gpio3: gpio@73f90000 { /* GPIO4 */
+			gpio4: gpio@73f90000 {
 				compatible = "fsl,imx51-gpio", "fsl,imx31-gpio";
 				reg = <0x73f90000 0x4000>;
 				interrupts = <56 57>;