arch/x86: include verstage.c only when verstage is a separate stage

Change-Id: Ia75205001f2443cb8221a0762f182aae01ee615e
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/26924
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/arch/x86/Makefile.inc b/src/arch/x86/Makefile.inc
index c15f829..d8430c5 100644
--- a/src/arch/x86/Makefile.inc
+++ b/src/arch/x86/Makefile.inc
@@ -180,10 +180,10 @@
 verstage-y += memcpy.c
 verstage-y += memmove.c
 verstage-$(CONFIG_X86_TOP4G_BOOTMEDIA_MAP) += mmap_boot.c
-# If C environment is used for bootblock it means there's no need
+# If verstage is a separate stage it means there's no need
 # for a chipset-specific car_stage_entry() so use the generic one
 # which just calls verstage().
-verstage-$(CONFIG_C_ENVIRONMENT_BOOTBLOCK) += verstage.c
+verstage-$(CONFIG_VBOOT_SEPARATE_VERSTAGE) += verstage.c
 
 verstage-$(CONFIG_COLLECT_TIMESTAMPS_TSC) += timestamp.c