tg3: Add PHY reset for 5717/5719/5720 in change ring and flow control paths

This patch has the fix to avoid PHY lockup with 5717/5719/5720 in change
ring and flow control paths. This patch solves the RX hang while doing
continuous ring or flow control parameters with heavy traffic from peer.

Signed-off-by: Siva Reddy Kallam <siva.kallam@broadcom.com>
Acked-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>