pinctrl: Add resource management devm_pinctrl_{register, unregister}

Add new member of devm wrappers for the pinctrl_register and
pinctrl_unregister in list of managed interfaces.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>