ipmi: change timeout and event poll to one second

The timeouts in IPMI are in the 1-5 second range in message handling, so a
1 second timeout is a reasonable thing to do.  This should help with
reducing power consumption on idle systems.

Signed-off-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>