This restores normal pre-r43715 200ms blink-period for the System LED we're all accustomed to see while our OpenWrt routers are booting.

Failsafe possibility will now be signalled with a new 100ms blinking, which is easily recognizable from the normal 200ms booting.

So no existing user will be scared by a new 500ms LED pattern, since such a slow pattern could easily be mistaken for something wrong... I was like "ok why my router is collapsing now, is this a bad flash, a kernel panic, or what else" when I've seen it for the first time ;)

Sorry for not having explained myself better in v1 of this patch.

Original:
Preinit, failsafe is possible: 200ms
Preinit, failsafe not possible anymore, booting normally: 200ms
Failsafe entered: 50ms

Now (after preinit_regular has been introduced):
Preinit, failsafe is possible: 200ms
Preinit, failsafe not possible anymore, booting normally: 500ms *here is the "offending" change*
Failsafe entered: 50ms

With my proposed patch:
Preinit, failsafe is possible: 100ms *indicate this condition with a new timing, that prompts the user to press the key if they want to start failsafe*
Preinit, failsafe not possible anymore, booting normally: 200ms *keep this as before*
Failsafe entered: 50ms

Signed-off-by: Vittorio Gambaletta <openwrt@vittgam.net>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@44056 3c298f89-4303-0410-b956-a3cf2f4a3e73