PCI: iproc: Switch to msi_create_parent_irq_domain()

PCI: iproc: Switch to msi_create_parent_irq_domain()

Switch to msi_create_parent_irq_domain() from pci_msi_create_irq_domain()
which was using legacy MSI domain setup.

Signed-off-by: Nam Cao <namcao@linutronix.de>
[mani: reworded commit message & squashed the kdoc cleanup patch]
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
[bhelgaas: rebase on dev_fwnode() conversion]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Link: https://patch.msgid.link/53946d74caf1fd134a1820eac82c3cf64d48779f.1750858083.git.namcao@linutronix.de