bnx2x: enlarge minimal alignemnt of data offset

This improves the performance of driver on machine with L1_CACHE_SHIFT of at
most 32 bytes [HW was planned for 64-byte aligned fastpath data].

Signed-off-by: Dmitry Kravkov <Dmitry.Kravkov@qlogic.com>
Signed-off-by: Yuval Mintz <Yuval.Mintz@qlogic.com>
Signed-off-by: Ariel Elior <Ariel.Elior@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/bnx2x/bnx2x.h

@@ -1508,8 +1508,10 @@ struct bnx2x {
 /* TCP with Timestamp Option (32) + IPv6 (40) */
 #define ETH_MAX_TPA_HEADER_SIZE		72
 
-	/* Max supported alignment is 256 (8 shift) */
-#define BNX2X_RX_ALIGN_SHIFT		min(8, L1_CACHE_SHIFT)
+	/* Max supported alignment is 256 (8 shift)
+	 * minimal alignment shift 6 is optimal for 57xxx HW performance
+	 */
+#define BNX2X_RX_ALIGN_SHIFT		max(6, min(8, L1_CACHE_SHIFT))
 
 	/* FW uses 2 Cache lines Alignment for start packet and size
 	 *