evas_object_text: Fix unused parameter

When we do Not build with BIDI_SUPPORT, then "const Eo *eo_obj" is
never used and thus spits out an unused parameter warning during
compile. This has been bugging me for quite some time now, so put in a
small patch to silence this warning.

src/lib/evas/canvas/evas_object_text.c

@@ -1154,6 +1154,8 @@ _evas_text_direction_get(const Eo *eo_obj, Evas_Text_Data *o)
         evas_object_render_pre_prev_cur_add(&obj->layer->evas->clip_changes,
                                             (Evas_Object *)eo_obj, obj);
      }
+#else
+   (void)eo_obj;
 #endif
 
    return (Efl_Text_Bidirectional_Type)o->bidi_dir;