PCI: dwc: Rename struct pcie_port to dw_pcie_rp

All of the DW PCIe core driver entities except the pcie_port struct have
names with the "dw_" prefix to distinguish local and common PCIe name
spaces, and endpoint-related entities have an "_ep" suffix.

Rename struct pcie_port to dw_pcie_rp to make it more consistent with other
names.

[bhelgaas: commit log]
Link: https://lore.kernel.org/r/20220624143428.8334-16-Sergey.Semin@baikalelectronics.ru


Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>