staging: usbip: README: we need to document the protocol

Document the protocol.
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/usbip/README

@@ -2,5 +2,6 @@ TODO:
 	- more discussion about the protocol
 	- testing
 	- review of the userspace interface
+	- document the protocol
 
 Please send patches for this code to Greg Kroah-Hartman <greg@kroah.com>