PCI: dwc: Call devm_pci_alloc_host_bridge() early in dw_pcie_host_init()

Move devm_pci_alloc_host_bridge() to the beginning of dw_pcie_host_init().

devm_pci_alloc_host_bridge() is generic code that doesn't depend on any DWC
resource, so moving it earlier keeps all the subsequent devicetree-related
code together.

[bhelgaas: reorder earlier in series]

Link: https://lore.kernel.org/r/20250315201548.858189-4-helgaas@kernel.org


Signed-off-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>