PCI: intel-gw: Rename intel_pcie_port to intel_pcie

Rename struct intel_pcie_port to intel_pcie to match the convention of
<driver>_pcie. No functional change intended.

Link: https://lore.kernel.org/r/20211223011054.1227810-11-helgaas@kernel.orgSigned-off-by: Fan Fei <ffclaire1224@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Rahul Tanwar <rtanwar@maxlinear.com>