x86/mce: Fix the MCE poll timer logic

In commit 82f7af09 ("x86/mce: Cleanup timer mess), Thomas just
forgot the "/ 2" there while cleaning up.

Signed-off-by: Chen Gong <gong.chen@linux.intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: bp@amd64.org
Cc: tony.luck@intel.com
Link: http://lkml.kernel.org/r/1338863702-9245-1-git-send-email-gong.chen@linux.intel.com


Signed-off-by: Ingo Molnar <mingo@kernel.org>