Merge branch 'amd-xgbe-fixes'

Shyam Sundar S K says:

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Bug fixes to amd-xgbe driver

General fixes on amd-xgbe driver are addressed in this series, mostly
on the mailbox communication failures and improving the link stability
of the amd-xgbe device.
====================

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