PCI: vmd: Fix suspend handlers defined-but-not-used warning

Fix the following warnings:

  drivers/pci/host/vmd.c:731:12: warning: ‘vmd_suspend’ defined but not used [-Wunused-function]
   static int vmd_suspend(struct device *dev)
              ^
  drivers/pci/host/vmd.c:739:12: warning: ‘vmd_resume’ defined but not used [-Wunused-function]
   static int vmd_resume(struct device *dev)
              ^

Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Bjorn Helgaas <helgaas@kernel.org>
Reviewed-by: Keith Busch <keith.busch@intel.com>