fix(seria): Fix const placement and if statement

The `const` prefix should be used for constant pointer of pointer here.
However, `const char **` is constant char instead.

The strncmp must be the condition of if statement here, but the if statement
is missing here which result the raw_message will always be false.

serializer/serializer.c

@@ -291,8 +291,9 @@ status_t ta_send_transfer_req_deserialize(const char* const obj,
 
   json_result = cJSON_GetObjectItemCaseSensitive(json_obj, "message_format");
   if (json_result != NULL) {
-    strncmp("trytes", json_result->valuestring, 6);
-    raw_message = false;
+    if (!strncmp("trytes", json_result->valuestring, 6)) {
+      raw_message = false;
+    }
   }
 
   json_result = cJSON_GetObjectItemCaseSensitive(json_obj, "message");
@@ -426,7 +427,7 @@ status_t ta_find_transactions_obj_res_serialize(
   return ret;
 }
 
-status_t receive_mam_message_serialize(char** obj, const char** res) {
+status_t receive_mam_message_serialize(char** obj, char** const res) {
   status_t ret = SC_OK;
   cJSON* json_root = cJSON_CreateObject();
   if (json_root == NULL) {

serializer/serializer.h

@@ -122,7 +122,7 @@ status_t ta_find_transactions_obj_res_serialize(
  * - SC_OK on success
  * - non-zero on error
  */
-status_t receive_mam_message_serialize(char** obj, const char** res);
+status_t receive_mam_message_serialize(char** obj, char** const res);
 
 /**
  * @brief Serialze type of send_mam_res_t to JSON string