Add new bootstage step for the main loop

Mark when we get to the main loop.
Signed-off-by: NSimon Glass <sjg@chromium.org>

common/main.c

@@ -376,6 +376,8 @@ void main_loop (void)
 	char bcs_set[16];
 #endif /* CONFIG_BOOTCOUNT_LIMIT */
 
+	bootstage_mark_name(BOOTSTAGE_ID_MAIN_LOOP, "main_loop");
+
 #ifdef CONFIG_BOOTCOUNT_LIMIT
 	bootcount = bootcount_load();
 	bootcount++;