ipmi: Start the timer and thread on internal msgs

The timer and thread were not being started for internal messages,
so in interrupt mode if something hung the timer would never go
off and clean things up.  Factor out the internal message sending
and start the timer for those messages, too.

Signed-off-by: Corey Minyard <cminyard@mvista.com>
Tested-by: Gouji, Masayuki <gouji.masayuki@jp.fujitsu.com>
Cc: stable@vger.kernel.org