ixgbe: fix input error statistics for UDP checksum

82599 errata "Integrity Error Reported for IPv4/UDP Packets
with Zero Checksum"

Obtained from: https://git.dpdk.org/dpdk/commit/?id=2ee14c8905e9

sys/dev/ixgbe/if_ix.c

@@ -1464,6 +1464,7 @@ ixgbe_update_stats_counters(struct ixgbe_softc *sc)
 	u32                   missed_rx = 0, bprc, lxon, lxoff, total;
 	u32                   lxoffrxc;
 	u64                   total_missed_rx = 0;
+	u64                   xec_value = 0;
 
 	stats->crcerrs += IXGBE_READ_REG(hw, IXGBE_CRCERRS);
 	stats->illerrc += IXGBE_READ_REG(hw, IXGBE_ILLERRC);
@@ -1579,6 +1580,13 @@ ixgbe_update_stats_counters(struct ixgbe_softc *sc)
 	IXGBE_SET_COLLISIONS(sc, 0);
 	IXGBE_SET_IQDROPS(sc, total_missed_rx);
 
+	/*
+	 * 82599 errata, UDP frames with a 0 checksum can be marked as checksum
+	 * errors.
+	 */
+	if (hw->mac.type != ixgbe_mac_82599EB)
+		xec_value = stats->xec;
+
 	/*
 	 * Aggregate following types of errors as RX errors:
 	 * - CRC error count,
@@ -1591,7 +1599,7 @@ ixgbe_update_stats_counters(struct ixgbe_softc *sc)
 	 * - oversized packets count,
 	 * - jabber count.
 	 */
-	IXGBE_SET_IERRORS(sc, stats->crcerrs + stats->illerrc + stats->xec +
+	IXGBE_SET_IERRORS(sc, stats->crcerrs + stats->illerrc + xec_value +
 	    stats->mpc[0] + stats->rlec + stats->ruc + stats->rfc + stats->roc +
 	    stats->rjc);
 } /* ixgbe_update_stats_counters */