net: mvneta: Fix big endian issue in mvneta_txq_desc_csum()

commit 0a198587 upstream.

This commit fixes the command value generated for CSUM calculation
when running in big endian mode.  The Ethernet protocol ID for IP was
being unconditionally byte-swapped in the layer 3 protocol check (with
swab16), which caused the mvneta driver to not function correctly in
big endian mode.  This patch byte-swaps the ID conditionally with
htons.

Cc: <stable@vger.kernel.org> # v3.13+
Signed-off-by: Thomas Fitzsimmons <fitzsim@fitzsim.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>

drivers/net/ethernet/marvell/mvneta.c

@@ -1182,7 +1182,7 @@ static u32 mvneta_txq_desc_csum(int l3_offs, int l3_proto,
 	command =  l3_offs    << MVNETA_TX_L3_OFF_SHIFT;
 	command |= ip_hdr_len << MVNETA_TX_IP_HLEN_SHIFT;
 
-	if (l3_proto == swab16(ETH_P_IP))
+	if (l3_proto == htons(ETH_P_IP))
 		command |= MVNETA_TXD_IP_CSUM;
 	else
 		command |= MVNETA_TX_L3_IP6;