Revert "net: bcmgenet: use RGMII loopback for MAC reset"

commit 612eb1c3 upstream.

This reverts commit 3a55402c.

This is not a good solution when connecting to an external switch
that may not support the isolation of the TXC signal resulting in
output driver contention on the pin.

A different solution is necessary.

Signed-off-by: Doug Berger <opendmb@gmail.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
[Adjusted to accommodate lack of commit 4f8d81b7]
Signed-off-by: Doug Berger <opendmb@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>