New fwnode_get_irq_byname() landed after an unrelated function
by ordering. Move fwnode_iomap(), so fwnode_get_irq*() APIs will
go together.

No functional change intended.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>