Merge branch 'phy-25G-BASE-R'

Steen Hegelund says:

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Add 25G BASE-R support

This series add the 25G BASE-R mode to the set modes supported.
This mode is used by the Sparx5 Switch for its 25G SerDes.
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Signed-off-by: David S. Miller <davem@davemloft.net>