hwmon: (coretemp) Fix checkpatch error

Fix:
ERROR: Macros with complex values should be enclosed in parenthesis

Cc: Fenghua Yu <fenghua.yu@intel.com>
Acked-By: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>