Merge branch 'net-improve-devres-helpers'

Bartosz Golaszewski says:

====================
net: improve devres helpers

So it seems like there's no support for relaxing certain networking devres
helpers to not require previously allocated structures to also be managed.
However the way mdio devres variants are implemented is still wrong and I
modified my series to address it while keeping the functions strict.

First two patches modify the ixgbe driver to get rid of the last user of
devm_mdiobus_free().

Patches 3, 4, 5 and 6 are mostly cosmetic.

Patch 7 fixes the way devm_mdiobus_register() is implemented.

Patches 8 & 9 provide a managed variant of of_mdiobus_register() and
last patch uses it in mtk-star-emac driver.

v1 -> v2:
- drop the patch relaxing devm_register_netdev()
- require struct mii_bus to be managed in devm_mdiobus_register() and
  devm_of_mdiobus_register() but don't store that information in the
  structure itself: use devres_find() instead
====================

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