Merge branch 'net-dsa-mv88e6xxx-add-support-for-MV88E6220'

Hubert Feurstein says:

====================
net: dsa: mv88e6xxx: add support for MV88E6220

This patch series adds support for the MV88E6220 chip to the mv88e6xxx driver.
The MV88E6220 is almost the same as MV88E6250 except that the ports 2-4 are
not routed to pins.

Furthermore, PTP support is added to the MV88E6250 family.

v2:
 - insert all 6220 entries in correct numerical order
 - introduce invalid_port_mask
 - move ptp_cc_mult* to ptp_ops and restored original ptp_adjfine code
 - added Andrews Reviewed-By to patch 2 and 4
====================

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