screen_ui: stage marker positioning

Small fix to position stage markers above screen margin.

Bug: 65556996
Test: Viewed graphics test
Change-Id: Idb4a56b06b8ec4e6653b3d3f3a446fa491f5ccb7
diff --git a/screen_ui.cpp b/screen_ui.cpp
index bc5c5c3..166d7b4 100644
--- a/screen_ui.cpp
+++ b/screen_ui.cpp
@@ -165,7 +165,7 @@
       int stage_height = gr_get_height(stageMarkerEmpty);
       int stage_width = gr_get_width(stageMarkerEmpty);
       int x = (gr_fb_width() - max_stage * gr_get_width(stageMarkerEmpty)) / 2;
-      int y = gr_fb_height() - stage_height;
+      int y = gr_fb_height() - stage_height - kMarginHeight;
       for (int i = 0; i < max_stage; ++i) {
         GRSurface* stage_surface = (i < stage) ? stageMarkerFill : stageMarkerEmpty;
         gr_blit(stage_surface, 0, 0, stage_width, stage_height, x, y);