bootstage: Add bootstage command

Now that there are a few features, add a bootstage command to access them.

bootstage report - prints a report
bootstage stash/unstash - stashes bootstage records in memory, reads them back

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/README b/README
index 5e00fcc..32e64d6 100644
--- a/README
+++ b/README
@@ -2384,6 +2384,10 @@
 		 29,916,167 26,005,792  bootm_start
 		 30,361,327    445,160  start_kernel
 
+		CONFIG_CMD_BOOTSTAGE
+		Add a 'bootstage' command which supports printing a report
+		and un/stashing of bootstage data.
+
 		CONFIG_BOOTSTAGE_FDT
 		Stash the bootstage information in the FDT. A root 'bootstage'
 		node is created with each bootstage id as a child. Each child