gpio: merrifield: Convert to use acpi_dev_get_first_match_dev()

acpi_dev_get_first_match_name() is deprecated and going to be removed
because it leaks a reference.

Convert the driver to use acpi_dev_get_first_match_dev() instead.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>