Add a config flag to enable time stamp collection

Add a new flag, make it dependent on EARLY_CBMEM_INIT

Change-Id: Idbebcaf298238f31a73e9eb4a9af7b03e857bc74
Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Reviewed-on: http://review.coreboot.org/712
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
Tested-by: build bot (Jenkins)
Reviewed-by: Rudolf Marek <r.marek@assembler.cz>

src/Kconfig

@@ -120,6 +120,13 @@ config EARLY_CBMEM_INIT
 	  stage. This could be useful when the rom stage wants to communicate
 	  some, for instance, execution timestamps.
 
+config COLLECT_TIMESTAMPS
+	bool "Create a table of timestamps collected during boot"
+	depends on EARLY_CBMEM_INIT
+	help
+	  Make coreboot create a table of timer id/timer value pairs to
+	  allow measuring time spent at different phases of the boot
+	  process.
 endmenu
 
 source src/mainboard/Kconfig