ehci functions. We can't assume that there will only be one ehci per device.
The existing code could not deal with:
Netmos MCS9990 Quad USB 2.0 Port (USB serial bus, interface 0x10) at pci1 dev 0 function 0 not configured
Netmos MCS9990 Quad USB 2.0 Port (USB serial bus, interface 0x20) at pci1 dev 0 function 1 not configured
Netmos MCS9990 Quad USB 2.0 Port (USB serial bus, interface 0x10) at pci1 dev 0 function 2 not configured
Netmos MCS9990 Quad USB 2.0 Port (USB serial bus, interface 0x20) at pci1 dev 0 function 3 not configured
Netmos MCS9990 Quad USB 2.0 Port (USB serial bus, interface 0x10) at pci1 dev 0 function 4 not configured
Netmos MCS9990 Quad USB 2.0 Port (USB serial bus, interface 0x20) at pci1 dev 0 function 5 not configured
Netmos MCS9990 Quad USB 2.0 Port (USB serial bus, interface 0x10) at pci1 dev 0 function 6 not configured
Netmos MCS9990 Quad USB 2.0 Port (USB serial bus, interface 0x20) at pci1 dev 0 function 7 not configured