PCI: dwc: Select PCI_HOST_COMMON for hisi

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.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Jingoo Han <jingoohan1@gmail.com>