intel/car/cache_as_ram_ht.inc: Prepare for dynamic CONFIG_RAMTOP

Change-Id: Idb0f621553e76e771a5d6f2d492675ccd989d947
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/15228
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
diff --git a/src/mainboard/aopen/dxplplusu/romstage.c b/src/mainboard/aopen/dxplplusu/romstage.c
index 1e78a97..5e7a159 100644
--- a/src/mainboard/aopen/dxplplusu/romstage.c
+++ b/src/mainboard/aopen/dxplplusu/romstage.c
@@ -20,6 +20,7 @@
 #include <stdlib.h>
 #include <console/console.h>
 #include <cpu/x86/bist.h>
+#include <cpu/intel/romstage.h>
 
 #include <southbridge/intel/i82801dx/i82801dx.h>
 #include <northbridge/intel/e7505/raminit.h>
@@ -34,8 +35,7 @@
 	return smbus_read_byte(device, address);
 }
 
-#include <cpu/intel/romstage.h>
-void main(unsigned long bist)
+void mainboard_romstage_entry(unsigned long bist)
 {
 	static const struct mem_controller memctrl[] = {
 		{