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/console/Kconfig

@@ -274,6 +274,7 @@ config CONSOLE_NE2K_IO_PORT
 	  boundary, qemu needs broader align)
 
 config CONSOLE_CBMEM
+	depends on (EARLY_CBMEM_INIT || DYNAMIC_CBMEM)
 	bool "Send console output to a CBMEM buffer"
 	default n
 	help