overlay: Enable “Panic Detection” mode

 * Change Ibf1370ff3cb539a9a54002a8704922744a3ca5d7 on fw/base
   added support for a security feature. This feature listens
   for multiple back button presses in succession and then
   returns the user to their home screen.

Change-Id: I5a386782ae2dcb0898491e1af48a73d6fb74a181