PCI: plda: Add host init/deinit and map bus functions

Add PLDA host plda_pcie_host_init()/plda_pcie_host_deinit() and map bus
function so vendors can use it to init PLDA PCIe host core.

Link: https://lore.kernel.org/linux-pci/20240328091835.14797-19-minda.chen@starfivetech.com


Signed-off-by: Minda Chen <minda.chen@starfivetech.com>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mason Huo <mason.huo@starfivetech.com>