ramips: fix mode switch gpio for AsiaRF AWM eval board

Fix a typo: gpio 21 is already used for the WPS led.  Gpio 20 is the
right one (tested) for the mode switch.  Confirmed that
/sys/kernel/debug/gpio state followed the position of the switch.

Signed-off-by: Russell Senior <russell@personaltelco.net>

SVN-Revision: 41858

target/linux/ramips/dts/AWM002-EVB-4M.dts

@@ -41,7 +41,7 @@
 		};
 		mode {
 			label = "mode";
-			gpios = <&gpio0 21 1>;
+			gpios = <&gpio0 20 1>;
 			linux,code = <0x32>;
 		};
 	};

target/linux/ramips/dts/AWM002-EVB-8M.dts

@@ -41,7 +41,7 @@
 		};
 		mode {
 			label = "mode";
-			gpios = <&gpio0 21 1>;
+			gpios = <&gpio0 20 1>;
 			linux,code = <0x32>;
 		};
 	};

target/linux/ramips/dts/AWM003-EVB.dts

@@ -56,7 +56,7 @@
 		};
 		mode {
 			label = "mode";
-			gpios = <&gpio0 21 1>;
+			gpios = <&gpio0 20 1>;
 			linux,code = <0x32>;
 		};
 	};