gpio: fix kernel-doc for of_gpio_need_valid_mask()

Fix kernel-doc for of_gpio_need_valid_mask().
Fixes this warning and uses correct Return: format.

../drivers/gpio/gpiolib-of.c:92: warning: Excess function parameter 'dev' description in 'of_gpio_need_valid_mask'

Fixes: f626d6df ("gpio: of: Break out OF-only code")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Cc: linux-gpio@vger.kernel.org
Link: https://lore.kernel.org/r/6c5d22c8-6e27-3314-9c46-701d932b11a6@infradead.org


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