x86, mcheck, therm_throt.c: Export symbol platform_thermal_notify to allow coretemp to handler intr

In therm_throt.c, commit
9e76a97e patch doesn't export
the symbol platform_thermal_notify.

Other drivers (e.g. drivers/hwmon/coretemp.c) can not find the
symbol platform_thermal_notify when defining threshould
interrupt handler.

Please apply this patch to allow threshold interrupt handler in
coretemp.

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Cc: R Durgadoss <durgadoss.r@intel.com>
Cc: khali@linux-fr.org <khali@linux-fr.org>
Cc: lm-sensors@lm-sensors.org <lm-sensors@lm-sensors.org>
Cc: Guenter Roeck <guenter.roeck@ericsson.com>
LKML-Reference: <20110121041239.GB26954@linux-os.sc.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>