pinctrl: Unconditionally assign .request()/.free()

The gpiochip_generic_request() and gpiochip_generic_free() functions can
now deal properly with chips that don't have any pin-ranges defined, so
they can be assigned unconditionally.

Suggested-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://lore.kernel.org/r/20200401200527.2982450-2-thierry.reding@gmail.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>