As a first step to consolidate the RNDIS implementations, break out
a common file with all the #defines and move it to <linux/rndis.h>.

This also deletes the immediate duplicated defines in the
<linux/rndis.h> file that yields a lot of compilation warnings.
Reviewed-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>