PCI: mvebu: Convert to use pci_host_bridge directly

Rather than using the ARM-specific pci_common_init_dev() API, use the
pci_host_bridge logic directly.

Unfortunately, we can't use devm_of_pci_get_host_bridge_resources(),
because the DT binding for describing PCIe apertures for this PCI
controller is a bit special, and we cannot retrieve them from the
'ranges' property. Therefore, we still have some special code to
handle this.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>