iio: mb1232: relax return value check for IRQ get

fwnode_irq_get() was changed to not return 0 anymore.

Drop check for return value 0.

Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/9e18cf49a8bb581a84c3fa548ea577e2a3eb840d.1690890774.git.mazziesaccount@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>