PCI: hisi: Constify dw_pcie_host_ops structure

Make this structure const as it is only stored in the ops field of a
pcie_port structure, which is of type const.  Done using Coccinelle.

Signed-off-by: Bhumika Goyal <bhumirks@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>