add "preinit_regular" diag.sh set_state argument

add "preinit_regular" diag.sh set_state argument

This new argument is used right after starting regular preinit (which
happens if failsafe wasn't triggered). The main purpose of "preinit"
argument is to indicate that failsafe can be triggered, however we were
missing a way to inform user that we don't wait for a trigger anymore.
With this change it's clear when failsafe mode can be triggered.

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@43715 3c298f89-4303-0410-b956-a3cf2f4a3e73