bootstage: Make use of BOOTSTAGE_ID_RUN_OS in show_boot_progress()

This changes the number 15 as used in boot_stage_progress() to use the
new name provided for it. This is a separate patch because it touches
so many files.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Mike Frysinger <vapier@gentoo.org>
diff --git a/board/a4m072/a4m072.c b/board/a4m072/a4m072.c
index 09a5a51..9485cfb 100644
--- a/board/a4m072/a4m072.c
+++ b/board/a4m072/a4m072.c
@@ -484,7 +484,7 @@
 	display_out_pos = 0;	/* reset output position */
 
 	/* we want to flush status 15 now */
-	if (status == 15)
+	if (status == BOOTSTAGE_ID_RUN_OS)
 		display_flush();
 }
 #endif