iio: proximity: mb1232: Switch to use fwnode_irq_get()

We have OF-centric variant of fwnode_irq_get() in the driver.
Replace it with a call to an agnostic implementation.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Andreas Klinger <ak@it-klinger.de>
Link: https://lore.kernel.org/r/20220413183123.20292-1-andriy.shevchenko@linux.intel.com


Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>