PCI: microchip: Move PLDA functions to pcie-plda-host.c

PCI: microchip: Move PLDA functions to pcie-plda-host.c

Move plda_pcie_setup_window() and plda_pcie_setup_iomems() to
pcie-plda-host.c so they can be shared by all PLDA-based drivers.

Link: https://lore.kernel.org/linux-pci/20240328091835.14797-10-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: Conor Dooley <conor.dooley@microchip.com>