[PATCH] ipmi_msghandler: inconsistent spin_lock usage

I found an inconsistent spin_lock usage in ipmi_smi_msg_received.

Signed-off-by: Hironobu Ishii <hishii@soft.fujitsu.com>
Cc: Corey Minyard <minyard@acm.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>