hwmon: (applesmc) Assign boolean values to a bool variable

Fix the following coccicheck warnings:

./drivers/hwmon/applesmc.c:568:6-23: WARNING: Assignment of
0/1 to bool variable.

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Zhong <abaci-bugfix@linux.alibaba.com>
Link: https://lore.kernel.org/r/1611124870-125658-1-git-send-email-abaci-bugfix@linux.alibaba.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>