[mpi_enc_test]: Fix memory leak of test args

Change-Id: Ica87ba3f77eb12e0b36b2ea0d607b4defbea9abb
Signed-off-by: Herman Chen <herman.chen@rock-chips.com>

test/mpi_enc_test.c

@@ -957,13 +957,14 @@ int main(int argc, char **argv)
 
     if (ret) {
         mpi_enc_test_help();
-        return ret;
+        goto DONE;
     }
 
     mpi_enc_test_cmd_show_opt(cmd);
 
     ret = mpi_enc_test(cmd);
 
+DONE:
     mpi_enc_test_cmd_put(cmd);
 
     return ret;