Merge remote-tracking branch 'kraxel/usb.37' into staging

* kraxel/usb.37:
  usb-redir: Improve some debugging messages
  usb-redir: Try to keep our buffer size near the target size
  usb-redir: Pre-fill our isoc input buffer before sending pkts to the host
  usb-redir: Dynamically adjust iso buffering size based on ep interval
  usb-redir: Clear iso / irq error when stopping the stream
  usb: link packets to endpoints not devices
  usb: add max_packet_size to USBEndpoint
  usb/debug: add usb_ep_dump
  usb-desc: USBEndpoint support
  usb: add ifnum to USBEndpoint
  usb: add USBEndpoint
  xhci: Initial xHCI implementation
  usb: add audio device model
  usb-desc: audio endpoint support
  usb: track altsetting in USBDevice
  usb: track configuration and interface count in USBDevice.
  usb-host: rip out legacy procfs support

diff --cc hw/usb.h
Simple merge