app: aboot: disable FRP feature and replace with stub code.

FRP system, currently uses static password to authenticate, which
is not safe.
Disable and replace frp_unlock with a stub code, that will take no action.
OEMs to implement their own authentication check to allow factory reset.

Change-Id: I2bf002a8167994ca087df2945c617396b59c695a
1 file changed