fix compliation warnings from runmode-af-packet.c

src/runmode-af-packet.c

@@ -755,13 +755,12 @@ int RunModeIdsAFPAutoFp(DetectEngineCtx *de_ctx)
  */
 int RunModeIdsAFPSingle(DetectEngineCtx *de_ctx)
 {
+    SCEnter();
+#ifdef HAVE_AF_PACKET
     int nafp = LiveGetDeviceCount();
     char *afp_dev = NULL;
     char *afp_devc = NULL;
 
-    SCEnter();
-#ifdef HAVE_AF_PACKET
-
     if (nafp > 1) {
         SCLogError(SC_ERR_RUNMODE,
                    "Can't use single runmode with multiple device");