PCI: dwc: Add dw_pcie_suspend_noirq(), dw_pcie_resume_noirq() stubs for !CONFIG_PCIE_DW_HOST

Previously pcie-designware.h declared dw_pcie_suspend_noirq() and
dw_pcie_resume_noirq() unconditionally, even though they were only
implemented when CONFIG_PCIE_DW_HOST was defined.

Add no-op stubs for them when CONFIG_PCIE_DW_HOST is not defined so
drivers that support both Root Complex and Endpoint modes don't need

Link: https://lore.kernel.org/r/20250117213810.GA656803@bhelgaas


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