Revert "CBMEM: Always have early initialisation"

This reverts commit de1fe7f655.

While things appeared to work, there were actually invalid references
to CAR storage after CAR was torn down on boards without
EARLY_CBMEM_INIT. It was discussed use of CAR_GLOBAL should be
restricted to boards that handle CAR migration properly.

Change-Id: I9969d2ea79c334a7f95a0dbb7c78065720e6ccae
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/3968
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@google.com>

src/Kconfig

@@ -170,9 +170,19 @@ config INCLUDE_CONFIG_FILE
 	    config                         0x8d740    raw          3324
 	    (empty)                        0x8e480    null         3610440
 
+config EARLY_CBMEM_INIT
+	bool
+	default n
+	help
+	  Make coreboot initialize the CBMEM structures while running in ROM
+	  stage. This is useful when the ROM stage wants to communicate
+	  some, for instance, execution timestamps. It needs support in
+	  romstage.c and should be enabled by the board's Kconfig.
+
 config DYNAMIC_CBMEM
 	bool "The CBMEM space is dynamically grown."
 	default n
+	select EARLY_CBMEM_INIT
 	help
 	  Instead of reserving a static amount of CBMEM space the CBMEM
 	  area grows dynamically.  CBMEM can be used both in romstage (after
@@ -180,7 +190,7 @@ config DYNAMIC_CBMEM
 
 config COLLECT_TIMESTAMPS
 	bool "Create a table of timestamps collected during boot"
-	default n
+	depends on (EARLY_CBMEM_INIT || DYNAMIC_CBMEM)
 	help
 	  Make coreboot create a table of timer-ID/timer-value pairs to
 	  allow measuring time spent at different phases of the boot process.