Input: iforce - use wait_event_interruptible_timeout

The timeout while() loops in iforce-packets.c lack a
set_current_state(TASK_INTERRUPTIBLE); call. The right solution is
to replace them with wait_event_interruptible_timeout().

Reported-by: Nishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: Vojtech Pavlik <vojtech@suse.cz>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>