patch 8.2.1228: scrollbars not flush against the window edges when maximised

Problem:    Scrollbars not flush against the window edges when maximised.
Solution:   Add padding. (Ken Takata, closes #5602, closes #6466)
diff --git a/src/gui_haiku.cc b/src/gui_haiku.cc
index 78ca7b2..60926f9 100644
--- a/src/gui_haiku.cc
+++ b/src/gui_haiku.cc
@@ -3665,6 +3665,22 @@
     }
 }
 
+    int
+gui_mch_get_scrollbar_xpadding(void)
+{
+    // TODO: Calculate the padding for adjust scrollbar position when the
+    // Window is maximized.
+    return 0;
+}
+
+    int
+gui_mch_get_scrollbar_ypadding(void)
+{
+    // TODO: Calculate the padding for adjust scrollbar position when the
+    // Window is maximized.
+    return 0;
+}
+
 void
 gui_mch_create_scrollbar(
 	scrollbar_T *sb,