gtpu: fix coverity issue

Fix coverity issue #210194 in gtpu-decap

Type: fix

Signed-off-by: Chenmin Sun <chenmin.sun@intel.com>
Change-Id: I5b172c8494527e7117c4e7e7083a8473165aa40f
diff --git a/src/plugins/gtpu/gtpu_decap.c b/src/plugins/gtpu/gtpu_decap.c
index 5e737d1..05c2138 100644
--- a/src/plugins/gtpu/gtpu_decap.c
+++ b/src/plugins/gtpu/gtpu_decap.c
@@ -1514,7 +1514,7 @@
           if (PREDICT_FALSE (t1->decap_next_index != GTPU_INPUT_NEXT_IP4_INPUT) &&
             (t1->decap_next_index != GTPU_INPUT_NEXT_IP6_INPUT))
           {
-            next1 = GTPU_FLOW_ERROR_PAYLOAD_ERROR;
+            error1 = GTPU_FLOW_ERROR_PAYLOAD_ERROR;
             next1 = GTPU_INPUT_NEXT_DROP;
             goto trace1;
           }
@@ -1643,7 +1643,7 @@
           if (PREDICT_FALSE (t0->decap_next_index != GTPU_INPUT_NEXT_IP4_INPUT) &&
               (t0->decap_next_index != GTPU_INPUT_NEXT_IP6_INPUT))
           {
-            next0 = GTPU_FLOW_ERROR_PAYLOAD_ERROR;
+            error0 = GTPU_FLOW_ERROR_PAYLOAD_ERROR;
             next0 = GTPU_INPUT_NEXT_DROP;
             goto trace00;
           }