gpio: gpio-rcar: Drop direct use of valid_mask

gpio: gpio-rcar: Drop direct use of valid_mask

The valid_mask member of the struct gpio_chip is unconditionally written
by the GPIO core at driver registration. It should not be directly
populated by the drivers. Hiding the valid_mask in struct gpio_device
makes it clear it is not meant to be directly populated by drivers. This
means drivers should not access it directly from the struct gpio_chip.

The gpio-rcar checks the valid mask in set/get_multiple() operations.
This is no longer needed [1]. Drop these checks.

Additionally, the valid_mask is needed for enabling the GPIO inputs at
probe time. Use the new valid_mask -getter function instead of accessing
it directly from the struct gpio_chip.

Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/e46441ba8a2840e6b48ec8d2ecd5919995a5675f.1741180097.git.mazziesaccount@gmail.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>