Without PCI_HOST_COMMON support enabled, we get a link error:
drivers/pci/dwc/built-in.o: In function `hisi_pcie_map_bus':
pcie-hisi.c:(.text+0x8860): undefined reference to `pci_ecam_map_bus'
drivers/pci/dwc/built-in.o: In function `hisi_pcie_almost_ecam_probe':
pcie-hisi.c:(.text+0x88b4): undefined reference to `pci_host_common_probe'
Add an explicit 'select', as the other users have.