x86/mce: Set up timer unconditionally

mce_timer must be passed to setup_timer() in all cases, no
matter whether it is going to be actually used. Otherwise, when
the CPU gets brought down, its call to del_timer_sync() will
never return, as the timer won't have a base associated, and
hence lock_timer_base() will loop infinitely.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: <stable@kernel.org>
LKML-Reference: <4B1DB831.2030801@jp.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>