pinctrl/amd: Drop pinctrl_unregister for devm_ registered device

It's not necessary to unregister pin controller device registered
with devm_pinctrl_register() and using pinctrl_unregister() leads
to a double free.

Fixes: 3bfd44306c65 ("pinctrl: amd: Add support for additional GPIO")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
static int amd_pinconf_group_get(struct pinctrl_dev *pctldev,
				unsigned int group,
				unsigned long *config)
{
	const unsigned *pins;
	unsigned npins;
	int ret;

	ret = amd_get_group_pins(pctldev, group, &pins, &npins);
	if (ret)
		return ret;

	if (amd_pinconf_get(pctldev, pins[0], config))
			return -ENOTSUPP;

	return 0;
}

static int amd_pinconf_group_get(struct pinctrl_dev *pctldev,
				unsigned int group,
				unsigned long *config)
{
	const unsigned *pins;
	unsigned npins;
	int ret;

	ret = amd_get_group_pins(pctldev, group, &pins, &npins);
	if (ret)
		return ret;

	if (amd_pinconf_get(pctldev, pins[0], config))
			return -ENOTSUPP;

	return 0;
}
