Revert "pinctrl: remove pinctrl_remove_gpio_range"

This reverts earlier commit which removed
pinctrl_remove_gpio_range(), because at that time there
weren't any more users of that routine. It was removed as the
removal of ranges was done in unregister of pinctrl.

But as we are now registering stuff from gpiolib, we may
remove and insert a gpio module multiple times. So, we
need this routine again.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>