Merge branch 'sja1105-xpcs'

Vladimir Oltean says:

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Port the SJA1105 DSA driver to XPCS

As requested when adding support for the NXP SJA1110, the SJA1105 driver
could make use of the common XPCS driver, to eliminate some hardware
specific code duplication.

This series modifies the XPCS driver so that it can accommodate the XPCS
instantiation from NXP switches, and the SJA1105 driver so it can expose
what the XPCS driver expects.

Tested on NXP SJA1105S and SJA1110A.

Changes in v3:
None. This is a resend of v2 which had "changes requested" even though
there was no direct feedback.
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Signed-off-by: David S. Miller <davem@davemloft.net>