pinctrl: core: use devres_release() instead of devres_destroy()

devres_release() can simplify the code, because devres_release()
will call the destructor for the resource as well as freeing
the devres data.

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Acked-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>