ARM: dts: kirkwood: Fix "debounce-interval" property misspelling

"debounce_interval" was never supported.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Gregory Clement <gregory.clement@free-electrons.com>
Cc: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>

arch/arm/boot/dts/kirkwood-pogoplug-series-4.dts

@@ -35,7 +35,7 @@ gpio_keys {
 		pinctrl-names = "default";
 
 		eject {
-			debounce_interval = <50>;
+			debounce-interval = <50>;
 			wakeup-source;
 			linux,code = <KEY_EJECTCD>;
 			label = "Eject Button";