gianfar: disable TX vlan based on kernel 2.6.x

2.6.x kernels require a similar logic change as commit e1653c3e
[gianfar: do vlan cleanup] and commit 51b8cbfc
[gianfar: fix bug caused by e1653c3e] introduces for newer kernels.

Since there is something wrong with tx vlan of gianfar nic driver,
in kernel(3.1+), tx vlan is disabled. But in kernel 2.6.x, tx vlan
is still enabled. Thus,gianfar nic driver can not support vlan
packets and non-vlan packets at the same time.
Signed-off-by: Zhu Yanjun <Yanjun.Zhu@windriver.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>

drivers/net/gianfar.c

@@ -365,7 +365,7 @@ static int gfar_probe(struct of_device *ofdev,
 	priv->vlgrp = NULL;
 
 	if (priv->device_flags & FSL_GIANFAR_DEV_HAS_VLAN)
-		dev->features |= NETIF_F_HW_VLAN_TX | NETIF_F_HW_VLAN_RX;
+		dev->features |= NETIF_F_HW_VLAN_RX;
 
 	if (priv->device_flags & FSL_GIANFAR_DEV_HAS_EXTENDED_HASH) {
 		priv->extended_hash = 1;
@@ -1451,12 +1451,6 @@ static void gfar_vlan_rx_register(struct net_device *dev,
 	priv->vlgrp = grp;
 
 	if (grp) {
-		/* Enable VLAN tag insertion */
-		tempval = gfar_read(&priv->regs->tctrl);
-		tempval |= TCTRL_VLINS;
-
-		gfar_write(&priv->regs->tctrl, tempval);
-
 		/* Enable VLAN tag extraction */
 		tempval = gfar_read(&priv->regs->rctrl);
 		tempval |= (RCTRL_VLEX | RCTRL_PRSDEP_INIT);