bnx2x: change FW GRO error message to WARN_ONCE

It's supposed to be impossible for TPA to give us anything else
than IPv4 or IPv6 here. But in case there is a way to reach this error
by some strange received frames, we don't want to flood the kernel log.
WARN_ONCE is better for this purpose.
Signed-off-by: Michal Schmidt <mschmidt@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c

@@ -743,7 +743,7 @@ static void bnx2x_gro_receive(struct bnx2x *bp, struct bnx2x_fastpath *fp,
 			bnx2x_gro_csum(bp, skb, bnx2x_gro_ipv6_csum);
 			break;
 		default:
-			BNX2X_ERR("Error: FW GRO supports only IPv4/IPv6, not 0x%04x\n",
+			WARN_ONCE(1, "Error: FW GRO supports only IPv4/IPv6, not 0x%04x\n",
 				  be16_to_cpu(skb->protocol));
 		}
 	}