common: Drop bootstage.h from common header

Move this fairly uncommon header out of the common header.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/timer/tsc_timer.c b/drivers/timer/tsc_timer.c
index 43cb2d8..04596ff 100644
--- a/drivers/timer/tsc_timer.c
+++ b/drivers/timer/tsc_timer.c
@@ -7,6 +7,7 @@
  */
 
 #include <common.h>
+#include <bootstage.h>
 #include <dm.h>
 #include <malloc.h>
 #include <time.h>