drivers/hwmon/pwm-fan.c:176:5: warning:
symbol 'pwm_fan_of_get_cooling_data' was not declared. Should it be static?
drivers/hwmon/pwm-fan.c:176:5: warning:
no previous prototype for 'pwm_fan_of_get_cooling_data'
pwm_fan_of_get_cooling_data is only used in the pwm-fan driver and thus should
be declared static.