net: stmmac: skip VLAN restore when VLAN hash ops are missing

stmmac_vlan_restore() unconditionally calls stmmac_vlan_update() when
NETIF_F_VLAN_FEATURES is set. On platforms where priv->hw->vlan (or
->update_vlan_hash) is not provided, stmmac_update_vlan_hash() returns
-EINVAL via stmmac_do_void_callback(), resulting in a spurious
"Failed to restore VLANs" error even when no VLAN filtering is in use.

Remove not needed comment.
Remove not used return value from stmmac_vlan_restore().

Tested on Orange Pi Zero 3.

Fixes: bd7ad51 ("net: stmmac: Fix VLAN HW state restore")
Signed-off-by: Michal Piekos <michal.piekos@mmpsystems.pl>
Link: https://patch.msgid.link/20260328-vlan-restore-error-v4-1-f88624c530dc@mmpsystems.pl
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: michalpiekos

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

@@ -156,7 +156,7 @@ static void stmmac_tx_timer_arm(struct stmmac_priv *priv, u32 queue);
 static void stmmac_flush_tx_descriptors(struct stmmac_priv *priv, int queue);
 static void stmmac_set_dma_operation_mode(struct stmmac_priv *priv, u32 txmode,
 					  u32 rxmode, u32 chan);
-static int stmmac_vlan_restore(struct stmmac_priv *priv);
+static void stmmac_vlan_restore(struct stmmac_priv *priv);
 
 #ifdef CONFIG_DEBUG_FS
 static const struct net_device_ops stmmac_netdev_ops;
@@ -6859,21 +6859,15 @@ static int stmmac_vlan_rx_kill_vid(struct net_device *ndev, __be16 proto, u16 vi
 	return ret;
 }
 
-static int stmmac_vlan_restore(struct stmmac_priv *priv)
+static void stmmac_vlan_restore(struct stmmac_priv *priv)
 {
-	int ret;
-
 	if (!(priv->dev->features & NETIF_F_VLAN_FEATURES))
-		return 0;
+		return;
 
 	if (priv->hw->num_vlan)
 		stmmac_restore_hw_vlan_rx_fltr(priv, priv->dev, priv->hw);
 
-	ret = stmmac_vlan_update(priv, priv->num_double_vlans);
-	if (ret)
-		netdev_err(priv->dev, "Failed to restore VLANs\n");
-
-	return ret;
+	stmmac_vlan_update(priv, priv->num_double_vlans);
 }
 
 static int stmmac_bpf(struct net_device *dev, struct netdev_bpf *bpf)