ath79: change phy-names to only usb
Both generic-ehci.yaml and generic-ohci.yaml state that phy-names is to
only be usb.
Signed-off-by: Rosen Penev <[email protected]>
Link: https://github.com/openwrt/openwrt/pull/17118
Signed-off-by: John Crispin <[email protected]>