apm821xx: remove gpio-interrupt cruft

This hunk became obsolete the moment when our
gpio-button-hotplug learned how to deal with
interrupt-supported gpio buttons. The gpio driver
never supported interrupt handling, so these
properties never served any use (outside of a
enhanced ppc4xx-gpio driver that was dropped).

Signed-off-by: Christian Lamparter <chunkeey@gmail.com>

target/linux/apm821xx/dts/netgear-wndr4700.dts

@@ -244,12 +244,6 @@
 
 &GPIO0 {
 	status = "okay";
-	#interrupt-cells = <2>;
-	interrupt-controller;
-	interrupts-extended = <&UIC1 0x14>,
-			      <&UIC1 0x1e>,
-			      <&UIC1 0x1f>,
-			      <&UIC2 0x19>;
 };
 
 &IIC0 {