hwmon: (w83627ehf) Fix memory leak in probe function

The driver probe function leaked memory if creating the cpu0_vid attribute file
failed. Fix by converting the driver to use devm_kzalloc.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Cc: stable@vger.kernel.org # 2.6.32+
Acked-by: Jean Delvare <khali@linux-fr.org>