Staging: USB/IP: add client driver

This adds the USB IP client driver

Brian Merrell cleaned up a lot of this code and submitted it for
inclusion.  Greg also did a lot of cleanup.

Signed-off-by: Brian G. Merrell <bgmerrell@novell.com>
Cc: Takahiro Hirofuchi <hirofuchi@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>