app/testpmd: fix checksum engine with GTP on 32-bit

[ upstream commit f7bfa1285fe943b5189a63bb1d427e823b7fcc20 ]

l2_len is not calculated correctly on 32-bit systems, resulting in
packet forwarding failure.

This patch fixes this issue by changing the l2_len calculation.

Fixes: dd827fa42a30 ("app/testpmd: fix GTP L2 length in checksum engine")

Signed-off-by: Shiyang He <shiyangx.he@intel.com>
Acked-by: Ferruh Yigit <ferruh.yigit@amd.com>

app/test-pmd/csumonly.c

@@ -246,7 +246,7 @@ parse_gtp(struct rte_udp_hdr *udp_hdr,
 		info->l4_proto = 0;
 	}
 
-	info->l2_len += gtp_len + sizeof(udp_hdr);
+	info->l2_len += gtp_len + sizeof(*udp_hdr);
 }
 
 /* Parse a vxlan header */