Fixes nuttx target warning

```
jerry-main.c: In function 'str_to_uint':
jerry-main.c:89:12: warning: assignment discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
   89 |     *out_p = num_str_p;
make[4]: Leaving directory '/home/runner/work/jerryscript/jerryscript/targets/os/nuttx'
make[3]: Leaving directory '/home/runner/work/jerryscript/apps'
```

JerryScript-DCO-1.0-Signed-off-by: Yonggang Luo [email protected]

Author: lygstate

targets/os/nuttx/jerry-main.c

@@ -70,8 +70,7 @@ print_help (char *name)
  * @return converted number
  */
 static uint32_t
-str_to_uint (const char *num_str_p, /**< string to convert */
-             char **out_p) /**< [out] end of the number */
+str_to_uint (const char *num_str_p) /**< string to convert */
 {
   assert (jerry_feature_enabled (JERRY_FEATURE_ERROR_MESSAGES));
 
@@ -84,11 +83,6 @@ str_to_uint (const char *num_str_p, /**< string to convert */
     num_str_p++;
   }
 
-  if (out_p != NULL)
-  {
-    *out_p = num_str_p;
-  }
-
   return result;
 } /* str_to_uint */
 
@@ -176,7 +170,7 @@ jerry_main (int argc, char *argv[])
     {
       if (++i < argc)
       {
-        debug_port = str_to_uint (argv[i], NULL);
+        debug_port = str_to_uint (argv[i]);
       }
       else
       {