The USB subsystem pipes internal reset notifications through
usb_handle_packet() with a special magic PID. This indirection
is a pretty pointless excercise as it ends up being handled by
usb_generic_handle_packet anyway.
Replace the USB_MSG_RESET with a usb_device_reset() function
which can be called directly. Also rename the existing usb_reset()
function to usb_port_reset() to avoid confusion.