modules/usb: cleanup remove old module names

delete cases for Kernel <3.10 (nop-usb-xceiv), <3.12 (phy-nop)

Signed-off-by: Dirk Neukirchen <dirkneukirchen@web.de>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@45733 3c298f89-4303-0410-b956-a3cf2f4a3e73