iio: proximity: sx9500: Assign interrupt from GpioIo()

iio: proximity: sx9500: Assign interrupt from GpioIo()

The commit 0f0796509c07

("iio: remove gpio interrupt probing from drivers that use a single interrupt")

removed custom IRQ assignment for the drivers which are enumerated via
ACPI or OF. Unfortunately, some ACPI tables have IRQ line defined as
GpioIo() resource and thus automatic IRQ allocation will fail.

Partially revert the commit 0f0796509c07 to restore original behaviour.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>