Merge branch 'dsa-fix-MV88E6131-tagging'

Andrew Lunn says:

====================
Fix MV88E6131 tagging

Marvell has two different tagging protocols for frames passed to a
swicth. There is the older DSA and the newer EDSA. Somewhere along the
way, we broke support for switches which only support DSA, by trying
to configure them to use EDSA. These patches add back support for
switches which only support DSA, by allowing the drivers to
dynamically indicate the tagging protocol they support to the DSA
core. This needs to be dynamic since the mv88e6xxx has to support two
protocols.

Thanks go to Jamie Lentin for reporting the problem, helping debug it,
providing some of the fix, and testing.
====================

Tested-By: Jamie Lentin <jm@lentin.co.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>