x86/mce: Cleanup timer mess

Use unsigned long for dealing with jiffies not int. Rename the
callback to something sensible. Use __this_cpu_read/write for
accessing per cpu data.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Borislav Petkov <borislav.petkov@amd.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>