wapi: correct scan return value

Signed-off-by: zhanghongyu <zhanghongyu@xiaomi.com>

wireless/wapi/src/wireless.c

@@ -1256,14 +1256,14 @@ int wapi_scan_stat(int sock, FAR const char *ifname)
           return 1;
         }
 
-      printf("err[%d]: %s\n", errno, strerror(errno));
-    }
-  else
-    {
       int errcode = errno;
       WAPI_IOCTL_STRERROR(SIOCGIWSCAN, errcode);
       ret = -errcode;
     }
+  else
+    {
+      ret = 0;
+    }
 
   return ret;
 }