Merge branch 'dsa-port-enabling'

Vivien Didelot says:

====================
net: dsa: port enabling

This patchset makes slave open and close symmetrical and provides
helpers for enabling or disabling a given DSA port.

Changes in v3:
  - save the phy_device change for a future patchset

Changes in v2:
  - do not remove the phy argument from port enable/disable
====================

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