arm64: dts: mediatek: mt7622-rfb1: remove wrong gpio-keys property

gpio-keys (regular, not polling) does not use "poll-interval" property.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20220617232124.7022-1-krzysztof.kozlowski@linaro.orgSigned-off-by: Matthias Brugger <matthias.bgg@gmail.com>

arch/arm64/boot/dts/mediatek/mt7622-rfb1.dts

@@ -40,7 +40,6 @@ cpu@1 {
 
 	gpio-keys {
 		compatible = "gpio-keys";
-		poll-interval = <100>;
 
 		key-factory {
 			label = "factory";