When the user executes certain ethtool commands such as -s, -A, -G, -L,
-r a phy reset or autonegotiate is performed which results in management
traffic being interrupted.

Add a warning in these cases.
Signed-off-by: NNithin Nayak Sujir <nsujir@broadcom.com>
Signed-off-by: NMichael Chan <mchan@broadcom.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>