linux-phytec-fsl

hwmon: (gpio_fan) Use error value returned from get_fan_speed_index()

get_fan_speed_index() returns -EINVAL in case of errors, only to have it
ignored and replaced with -ENODEV. Make it return -ENODEV and use it.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>