Convert ipmi_watchdog to also use module option `nowayout' as is done in
other watchdog drivers.

From: Corey Minyard <cminyard@mvista.com>

   The patch is good (same style as other watchdogs), but needs to have
   some documentation updated.  I've tacked that on.
Signed-off-by: Arkadiusz Miskiewicz <arekm@pld-linux.org>
Signed-off-by: Corey Minyard <minyard@acm.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>