Optional Properties:
- linux,no-autorepeat: do no enable autorepeat feature.
- wakeup-source: use any event on keypad as wakeup event.
+ (Legacy property supported: "linux,wakeup")
- debounce-delay-ms: debounce interval in milliseconds
- col-scan-delay-us: delay, measured in microseconds, that is needed
before we can scan keypad after activating column gpio