[PATCH] ipw2100: RF kill switch timer power save

Similar patch to ipw2200. Round the timer used for RF kill
switch off to 1 second boundary to save power.
Build tested only, don't have this hardware.

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>