boot_stats: add support for bootup timestamps

Bootup timestamps can be logged at various points and
made available to the kernel through shared memory.
API implementation is platform specific and this change
only adds a dummy function.

Change-Id: I930d3385125ab3d8086518a8bc4481892d2bb34d
diff --git a/platform/init.c b/platform/init.c
index 30f3e51..0c5a850 100644
--- a/platform/init.c
+++ b/platform/init.c
@@ -23,6 +23,7 @@
 #include <err.h>
 #include <debug.h>
 #include <platform.h>
+#include <boot_stats.h>
 
 /*
  * default implementations of these routines, if the platform code
@@ -90,3 +91,7 @@
 __WEAK ce_clock_init(void)
 {
 }
+
+__WEAK void bs_set_timestamp(enum bs_entry bs_id)
+{
+}