ravb: Add aligned_tx to struct ravb_hw_info

R-Car Gen2 needs a 4byte aligned address for the transmission buffer,
whereas R-Car Gen3 doesn't have any such restriction.

Add aligned_tx to struct ravb_hw_info to select the driver to choose
between aligned and unaligned tx buffers.
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/renesas/ravb.h

@@ -990,6 +990,7 @@ enum ravb_chip_id {
 
 struct ravb_hw_info {
 	enum ravb_chip_id chip_id;
+	unsigned aligned_tx: 1;
 };
 
 struct ravb_private {

drivers/net/ethernet/renesas/ravb_main.c

@@ -1930,6 +1930,7 @@ static const struct ravb_hw_info ravb_gen3_hw_info = {
 
 static const struct ravb_hw_info ravb_gen2_hw_info = {
 	.chip_id = RCAR_GEN2,
+	.aligned_tx = 1,
 };
 
 static const struct of_device_id ravb_match_table[] = {
@@ -2140,7 +2141,7 @@ static int ravb_probe(struct platform_device *pdev)
 	ndev->max_mtu = 2048 - (ETH_HLEN + VLAN_HLEN + ETH_FCS_LEN);
 	ndev->min_mtu = ETH_MIN_MTU;
 
-	priv->num_tx_desc = info->chip_id == RCAR_GEN2 ?
+	priv->num_tx_desc = info->aligned_tx ?
 		NUM_TX_DESC_GEN2 : NUM_TX_DESC_GEN3;
 
 	/* Set function */