Merge branch 'net-dsa-bcm_sf2-Ensure-MDIO-diversion-is-used'

Florian Fainelli says:

====================
net: dsa: bcm_sf2: Ensure MDIO diversion is used

Changes in v2:

- export of_update_property() to permit building bcm_sf2 as a module
- provided a better explanation of the problem being solved after
  explaining it to Andrew during the v1 review
====================

Signed-off-by: Jakub Kicinski <kuba@kernel.org>