pinctrl: intel: Simplify code with cleanup helpers

Use macros defined in linux/cleanup.h to automate resource lifetime
control in the driver.

While at it, unify the variables and approach in intel_gpio_irq_*().
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>