Merge branch 'mv88e6xxx-Support-more-SERDES-interfacxes'

Andrew Lunn says:

====================
net: dsa: mv88e6xxx: Support more SERDES interfacxes

Currently the SERDES interfaces for ports 9 and 10 on the mv88e6390x
are supported, allowing upto 10G. However, when unused, these SERDES
interfaces can be used by some of the lower ports for 1000Base-X.

The tricky bit here is ordering. The SERDES have to become free from
ports 9 or 10 before they can be used with lower ports. Normally, this
would happen only when these ports would be configured up, which is
too late. So at probe time, defaulting ports 9 and 10 to 1000BaseX
frees them for use with lower ports. If they are actually needed, they
will be taken back when port 9 and 10 goes up.
====================

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