ARM: dts: kirkwood: Fix polarity of GPIO fan lines

These two lines are active high, not active low. The bug was
found when we changed the kernel to respect the polarity defined
in the device tree.

Fixes: 1b90e06b

 ("ARM: kirkwood: Use devicetree to define DNS-32[05] fan")
Cc: Jamie Lentin <jm@lentin.co.uk>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Gregory Clement <gregory.clement@bootlin.com>
Cc: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Cc: Julien D'Ascenzio <jdascenzio@posteo.net>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Jamie Lentin <jm@lentin.co.uk>
Reported-by: Julien D'Ascenzio <jdascenzio@posteo.net>
Tested-by: Julien D'Ascenzio <jdascenzio@posteo.net>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>