bootstage: arm: Add bootstage calls in board and bootm

Add calls to bootstage before and after relocation, and just
before jumping to the OS.

The idea here is you can call bootstage_report() to get a report.
Additionally, if you define CONFIG_BOOTSTAGE_REPORT then a report is
printed automatically by U-Boot just before jumping to the kernel.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/lib/bootm.c b/arch/arm/lib/bootm.c
index f114cd6..2961ab2 100644
--- a/arch/arm/lib/bootm.c
+++ b/arch/arm/lib/bootm.c
@@ -83,6 +83,10 @@
 static void announce_and_cleanup(void)
 {
 	printf("\nStarting kernel ...\n\n");
+	bootstage_mark_name(BOOTSTAGE_ID_BOOTM_HANDOFF, "start_kernel");
+#ifdef CONFIG_BOOTSTAGE_REPORT
+	bootstage_report();
+#endif
 
 #ifdef CONFIG_USB_DEVICE
 	{