Whoops, I missed something.  You should apply this patch too.

The RNDIS spec license agreement does NOT require tacking any
GPL-incompatible restrictions on the results of _using_ the
spec:

   "... may be used solely for the purpose of implementing
    the RNDIS protocol message set to interface with ..."
   (the two cases identified in the text)

And that's all the implementation does -- end of story.