USB: OHCI: add missing PCI PM callbacks to ohci-pci.c

Commit c1117afb (USB: OHCI: make ohci-pci a separate driver)
neglected to preserve the entries for the pci_suspend and pci_resume
driver callbacks.  As a result, OHCI controllers don't work properly
during suspend and after hibernation.

This patch adds the missing callbacks to the driver.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-and-tested-by: Steve Cotton <steve@s.cotton.clara.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>