net: stmmac: remove unnecessary netif_carrier_off()

It is incorrect to call netif_carrier_off(), or in fact any driver
teardown, before unregister_netdev() has been called.

unregister_netdev() unpublishes the network device from userspace, and
takes the interface down if it was up prior to returning. Therefore,
once the call has returned, we are guaranteed that .ndo_stop() will
have been called for an interface that was up. Phylink will take the
carrier down via phylink_stop(), making any manipulation of the carrier
in the remove path unnecessary.

In the stmmac_release() path, the netif_carrier_off() call follows the
call to phylink_stop(), so this call is redundant.
Reviewed-by: Andrew Halaney <ahalaney@redhat.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Serge Semin <fancer.lancer@gmail.com>
Link: https://lore.kernel.org/r/E1sCErZ-00EOPx-PF@rmk-PC.armlinux.org.ukSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

@@ -4088,8 +4088,6 @@ static int stmmac_release(struct net_device *dev)
 	if (priv->plat->serdes_powerdown)
 		priv->plat->serdes_powerdown(dev, priv->plat->bsp_priv);
 
-	netif_carrier_off(dev);
-
 	stmmac_release_ptp(priv);
 
 	pm_runtime_put(priv->device);
@@ -7806,7 +7804,6 @@ void stmmac_dvr_remove(struct device *dev)
 
 	stmmac_stop_all_dma(priv);
 	stmmac_mac_set(priv, priv->ioaddr, false);
-	netif_carrier_off(ndev);
 	unregister_netdev(ndev);
 
 #ifdef CONFIG_DEBUG_FS