firmware: usb: add usb_mdio config option and set the default to 0x5000
Use: usb_mdio=0x7000 to revert the behaviour

kernel: dwc_otg: Don't issue traffic to LS devices in FS mode
See: https://github.com/raspberrypi/linux/pull/390

kernel: Add AppleTalk module
See: https://github.com/raspberrypi/linux/issues/386