ARM: at91/dts: at91sam9g20ek_common: Fix typos in buttons labels.

Signed-off-by: Marek Belisko <marek.belisko@open-nandra.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>

arch/arm/boot/dts/at91sam9g20ek_common.dtsi

@@ -126,14 +126,14 @@ gpio_keys {
 		#size-cells = <0>;
 
 		btn3 {
-			label = "Buttin 3";
+			label = "Button 3";
 			gpios = <&pioA 30 1>;
 			linux,code = <0x103>;
 			gpio-key,wakeup;
 		};
 
 		btn4 {
-			label = "Buttin 4";
+			label = "Button 4";
 			gpios = <&pioA 31 1>;
 			linux,code = <0x104>;
 			gpio-key,wakeup;