bnx2x: Use correct FW constant for header padding

the value of the constant is the same, but it's clearer to use original
constant provided by HSI

Signed-off-by: Dmitry Kravkov <dmitry@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/bnx2x/bnx2x_cmn.c b/drivers/net/bnx2x/bnx2x_cmn.c
index afff58c..1966cee 100644
--- a/drivers/net/bnx2x/bnx2x_cmn.c
+++ b/drivers/net/bnx2x/bnx2x_cmn.c
@@ -831,7 +831,7 @@
 	int i, j;
 
 	bp->rx_buf_size = bp->dev->mtu + ETH_OVREHEAD + BNX2X_RX_ALIGN +
-		BNX2X_FW_IP_HDR_ALIGN_PAD;
+		IP_HEADER_ALIGNMENT_PADDING;
 
 	DP(NETIF_MSG_IFUP,
 	   "mtu %d  rx_buf_size %d\n", bp->dev->mtu, bp->rx_buf_size);