pinctrl: armada-37xx: swap polarity on LED group

The configuration registers for the LED group have inverted
polarity, which puts the GPIO into open-drain state when used in
GPIO mode.  Switch to '0' for GPIO and '1' for LED modes.

Fixes: 87466ccd

 ("pinctrl: armada-37xx: Add pin controller support for Armada 37xx")
Signed-off-by: Patrick Williams <alpawi@amazon.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20191001155154.99710-1-alpawi@amazon.com


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>