treewide: rename pinctrl_gpio_can_use_line_new()

Now that pinctrl_gpio_can_use_line() is no longer used, let's drop the
'_new' suffix from its improved variant.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>