Restore the old behavior of ehci_setup_phy() and ohci_setup_phy() to
return success when generic_phy_get_by_index() return -ENOENT.
Fixes: 84e561407a ("phy: Add generic_{setup,shutdown}_phy() helpers")
Fixes: 10005004db ("usb: ohci: Make usage of generic_{setup,shutdown}_phy() helpers")
Fixes: 083f8aa978 ("usb: ehci: Make usage of generic_{setup,shutdown}_phy() helpers")
Fixes: 75341e9c16 ("usb: ehci: Remove unused ehci_{setup,shutdown}_phy() helpers")
Signed-off-by: Jonas Karlman <jonas@kwiboo.se>