pinctrl: bcm2835: don't -EINVAL on alternate funcs from get_direction()

Since commit 9d846b1a ("gpiolib: check the return value of
gpio_chip::get_direction()") we check the return value of the
get_direction() callback as per its API contract. This driver returns
-EINVAL if the pin in question is set to one of the alternative
(non-GPIO) functions. This isn't really an error that should be
communicated to GPIOLIB so default to returning the "safe" value of
INPUT in this case. The GPIO subsystem does not have the notion of
"unknown" direction.

Fixes: 9d846b1a ("gpiolib: check the return value of gpio_chip::get_direction()")
Reported-by: Mark Brown <broonie@kernel.org>
Closes: https://lore.kernel.org/all/Z7VFB1nST6lbmBIo@finisterre.sirena.org.uk/


Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Stefan Wahren <wahrenst@gmx.net>
Link: https://lore.kernel.org/20250219102750.38519-1-brgl@bgdev.pl


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