boot state: remove drain timers option

boot state: remove drain timers option

Internally there were states that had an attribute to
indicate that the timers needed to be drained. Now that
there is a way to block state transitions rely on this
ability instead of draining timers. The timers will
drain themselves when a state is blocked.

Change-Id: I59be9a71b2fd5a17310854d2f91c2a8957aafc28
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/3205
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>