dwrite: Fix potential null pointer dereference in GetInlineObject() (Coverity).

dlls/dwrite/layout.c

@@ -2016,8 +2016,11 @@ static HRESULT WINAPI dwritetextlayout_GetInlineObject(IDWriteTextLayout2 *iface
 
     TRACE("(%p)->(%u %p %p)\n", This, position, object, r);
 
+    if (position >= This->len)
+        return S_OK;
+
     range = get_layout_range_by_pos(This, position);
-    *object = range ? range->object : NULL;
+    *object = range->object;
     if (*object)
         IDWriteInlineObject_AddRef(*object);