fsm: Introduce default time-out handling

If a FSM doesn't specify any timer_cb, simply terminate the FSM by
default on time-out.  This is a reasonable default for most cases, and
avoids copy+pasting a one-line timer_cb function in every FSM.

Also, even if there is a timer_cb, let it have a return value to decide
if the core should terminate after return from timer_cb or not.

Change-Id: I0461a9593bfb729c82b7d1d1cf9f30b1079d0212
2 files changed