net: mvpp2: set the GMAC, XLG MAC, XPCS and MPCS in reset when a port is down

This patch adds calls in the stop() helper to ensure both MACs and
both PCS blocks are set in reset when the user manually sets a port
down. This is done so that we have the exact same block reset states at
boot time and when a port is set down.
Signed-off-by: NAntoine Tenart <antoine.tenart@bootlin.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c

@@ -3525,6 +3525,9 @@ static int mvpp2_stop(struct net_device *dev)
 
 	cancel_delayed_work_sync(&port->stats_work);
 
+	mvpp2_mac_reset_assert(port);
+	mvpp22_pcs_reset_assert(port);
+
 	return 0;
 }