Merge remote-tracking branch 'kraxel/usb.49' into staging

* kraxel/usb.49:
  usb-uhci: update irq line on reset
  usb: add serial number generator
  usb-redir: Not finding an async urb id is not an error
  usb-redir: Reset device address and speed on disconnect
  usb-redir: An interface count of 0 is a valid value
  usb-xhci: fix bit test
  usb-xhci: Use PCI DMA helper functions
  usb-host: fix zero-length packets
  usb-host: don't dereference invalid iovecs
  usb-storage: fix request canceling
  usb-ehci: Ensure frindex writes leave a valid frindex value
  usb-ehci: add missing usb_packet_init() call
  usb-ehci: remove hack