Merge pull request #211 from petejohanson/core/keymap-port-event-exploration

Use PORT events for kscan matrix interrupts, add option for deep sleep.

app/boards/arm/nice_nano/nice_nano.dts

@@ -31,6 +31,10 @@
 
 };
 
+&gpiote {
+	status = "okay";
+};
+
 &gpio0 {
 	status = "okay";
 };