hwmon: (pwm-fan) stop fan on shutdown

hwmon: (pwm-fan) stop fan on shutdown

The pwm-fan driver stops the fan in suspend but leaves the fan on in
shutdown.  It seems strange to leave the fan on in shutdown because there
is no use case in my mind and the gpio-fan driver on the other hand stops
in shutdown.

This change turns off the fan in shutdown.  If anyone complains then we'll
add an optional property to switch the behavior.

Cc: Rob Herring <robh+dt@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Kamil Debski <kamil@wypas.org>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Link: https://lore.kernel.org/r/1579534344-11694-1-git-send-email-akinobu.mita@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>