AGESA: Use common romstage ram stack

Change-Id: Ie120360fa79aa0f6f6d82606838404bb0b0d9681
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/15466
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/lib/Makefile.inc

@@ -81,6 +81,7 @@ ramstage-$(CONFIG_PRIMITIVE_MEMTEST) += primitive_memtest.c
 romstage-$(CONFIG_CACHE_AS_RAM) += ramtest.c
 romstage-$(CONFIG_GENERIC_GPIO_LIB) += gpio.c
 romstage-y += romstage_stack.c
+ramstage-y += romstage_stack.c
 romstage-y += stack.c
 ramstage-y += rtc.c