Merge branch 'bcmgenet-start-stop-sequence-refinement'

Doug Berger says:

====================
net: bcmgenet: start/stop sequence refinement

This commit set is the result of an investigation into an issue that
occurred when bringing the interface up and down repeatedly with an
external 100BASE-T PHY. In some cases the MAC would experience mass
receive packet duplication that could in rare cases lead to a stall
from overflow.  The fix for this is contained in the third commit.

The first 3 commits represent bug fixes that should be applied to the
net repository and are candidates for backporting to stable releases.
The remaining commits are enhancements which is why the set is being
submitted to net-next but they are implemented on top of the fixes.

The first fix is provided as justification for why the set isn't
split between a net submission and a net-next submission.
====================

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