(1) Now the Ethernet is completely re-initialized when an error occurs by means of taking the interface down and back up but the PHY is _not_ renegotiated for that case because that is very time consuming and an error in the Ethernet is no reflection on the state of the PHY anyway.
(2) Explicitly sets the expected PHY address to zero (this could be moved into the config) rather than searching for it which takes ages, and it's zero anyway for this board (that's the broadcast address, and anything that cannot respond on that has multiple PHYs, so that would be a new board).
(3) Allows for the renegotiation of the PHY to be optional when a reset is needed. If a non-renegotiated reset doesn't result in good comms to the PHY then it'll automatically be escalated to a renegotiated one.
(4) Only performs a reset for errors that need it (the CRITICAL_ERROR define). The list of errors that need reset are somewhat arbitrarily chosen based on my prejudices and might need to be revisited, but certainly the jabber errors don't need reset, the partial packet is thrown away by the layer above anyway.
(5) Re-loads the multicast table on reset.
(6) Adds a bit more logging into the imxrt Ethernet module.
