regulator: core: Fix regualtor_ena_gpio_free not to access pin after freeing

After freeing pin from regulator_ena_gpio_free, loop can access
the pin. So this patch fixes not to access pin after freeing.

Signed-off-by: Seung-Woo Kim <sw0312.kim@samsung.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
static int _notifier_call_chain(struct regulator_dev *rdev,
				  unsigned long event, void *data)
{
	/* call rdev chain first */
	return blocking_notifier_call_chain(&rdev->notifier, event, data);
}

static int _notifier_call_chain(struct regulator_dev *rdev,
				  unsigned long event, void *data)
{
	/* call rdev chain first */
	return blocking_notifier_call_chain(&rdev->notifier, event, data);
}
