fix: correct OTA state file byte count checks

ql-application/threadx/interface/custom_app/mqtt.c

@@ -168,7 +168,7 @@ static int ota_state_save(const char *previous_version, const char *target_versi
     }
 
     ret = ql_fwrite(&state, sizeof(state), 1, fp);
-    if (ret != 1) {
+    if (ret != (int)sizeof(state)) {
         RLOGE("OTA state write failed: %d", ret);
         ql_fclose(fp);
         ql_remove(OTA_STATE_TMP_FILE);
@@ -211,7 +211,7 @@ static int ota_state_load(ota_state_t *state)
     memset(state, 0, sizeof(*state));
     ret = ql_fread(state, sizeof(*state), 1, fp);
     ql_fclose(fp);
-    if (ret != 1) {
+    if (ret != (int)sizeof(*state)) {
         RLOGE("OTA state read failed: %d", ret);
         return -1;
     }