CBMEM: Always build for x86 romstage

Always build CBMEM for romstage, even for boards that will not use it.
We further restrict car_migrate_variables() runs to non-ROMCC boards without
BROKEN_CAR_MIGRATE.

This fixes regression of commit 71b21455 that broke CBMEM console support
for boards with a combination of !EARLY_CBMEM_INIT && !HAVE_ACPI_RESUME.

Change-Id: Ife91d7baebdc9bd1e086896400059a165d3aa90f
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/7877
Tested-by: build bot (Jenkins)
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>

src/cpu/x86/Makefile.inc

@@ -1,6 +1,5 @@
 ifeq ($(CONFIG_ARCH_ROMSTAGE_X86_32),y)
-romstage-$(CONFIG_EARLY_CBMEM_INIT) += car.c
-romstage-$(CONFIG_BROKEN_CAR_MIGRATE) += car.c
+romstage-$(CONFIG_CACHE_AS_RAM) += car.c
 endif
 
 subdirs-$(CONFIG_PARALLEL_MP) += name

src/cpu/x86/car.c

@@ -73,7 +73,7 @@ void *car_get_var_ptr(void *var)
 	return &migrated_base[offset];
 }
 
-void car_migrate_variables(void)
+static void do_car_migrate_variables(void)
 {
 	void *migrated_base;
 	car_migration_func_t *migrate_func;
@@ -102,3 +102,9 @@ void car_migrate_variables(void)
 		migrate_func++;
 	}
 }
+
+void car_migrate_variables(void)
+{
+	if (!IS_ENABLED(CONFIG_BROKEN_CAR_MIGRATE))
+		do_car_migrate_variables();
+}