pinctrl: intel: Fix compilation warning when !CONFIG_PM_SLEEP

We get following warning when CONFIG_PM_SLEEP is not set

  warning: ‘intel_gpio_irq_init’ defined but not used [-Wunused-function]

Since the function is only called from intel_pinctrl_resume() move it
inside CONFIG_PM_SLEEP guard as well.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>