Merge branch 'dsa2-pdata-prepatory-patches'

Florian Fainelli says:

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net: dsa: Preparatory patches

This patch series extracts the 4 patches of the larger: net: dsa: Support for
pdata in dsa2 while we wait for feedback from Greg KH on the device references.

Changes in v2:

- rebased properly after the multi-MDIO bus support added to mv88e6xxx
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Signed-off-by: David S. Miller <davem@davemloft.net>