Merge branch '6lowpan'

Tony Cheneau says:

====================
This patchset fixes serious bugs within the 6LoWPAN modules. I wrote a script
(available at [1]) to prove the issues are real.  One can try and see that
without these patches, most of the test fail (e.g. packet dropped by the
receiver or node crashing). With all patches applied, all tests succeed. The
tests themselves are very basic: sending ICMP packets, sending UDP packets,
sending TCP packets, varying size of the packets. This actually triggers some
6LoWPAN specific code, namely fragmentation, packet reassembly and header
compression.

This code passed the checkpatch.pl tool with a few warnings, that I believe
are OK. It should apply cleanly on the latest net-next.

[1]: https://github.com/tcheneau/linux802154-regression-tests
====================

Signed-off-by: David S. Miller <davem@davemloft.net>