e1000: Retry transient MDIC failures on modern PCHHEADmain

Some Meteor Lake and newer systems sporadically fail an MDIC PHY
transaction while the MAC and PHY clocks synchronize.  Retry twice
before reporting the transaction failure.

Disable retries around PHY interface transitions where an MDI error
is expected.  Preserve and restore the configured retry count on every
exit from those flows.

This follows DPDK commit bdca22d62ff0, extended to the PTP and NVP PCH
types.

MFC after:	2 weeks

0 files changed, 0 insertions, 0 deletions