USB: xhci: Fix Link TRB handoff bit twiddling.

Make sure to preserve all bits *except* the TRB_CHAIN bit when giving a
Link TRB to the hardware.  We need to save things like TRB type and the
toggle bit in the control dword.

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>