We're getting a reference RPi's firmware node in order to be able to
communicate with it's driver. We should decrease the reference count on
the dt node after being done with it.
Fixes: a98d90e7d588 ("gpio: raspberrypi-exp: Driver for RPi3 GPIO expander via mailbox service") Signed-off-by: Nicolas Saenz Julienne <[email protected]> Signed-off-by: Linus Walleij <[email protected]>