6lowpan: nhc: add other known rfc6282 compressions

This patch adds other known rfc6282 compression formats to the nhc
framework. These compression formats are known but not implemented yet.
For now this is useful to printout a warning which compression format
isn't supported.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Cc: Martin Townsend <mtownsend1973@gmail.com>
Reviewed-by: Stefan Schmidt <s.schmidt@samsung.com>
Acked-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>