include: update cbmem_possibly_online for vboot_before_bootblock

cbmem is not online when vboot runs before the bootblock. Update the
macro to reflect that.

BUG=b:158124527
TEST=Build & boot psp_verstage on trembyle

Signed-off-by: Martin Roth <martin@coreboot.org>
Change-Id: I6fb4ad04f276f2358ab9d4d210fdc7a34a93a5bb
Reviewed-on: https://review.coreboot.org/c/coreboot/+/42066
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Raul Rangel <rrangel@chromium.org>
diff --git a/src/include/cbmem.h b/src/include/cbmem.h
index 96be108..f88cfb7 100644
--- a/src/include/cbmem.h
+++ b/src/include/cbmem.h
@@ -160,7 +160,7 @@
 	if (ENV_BOOTBLOCK)
 		return 0;
 
-	if (ENV_SEPARATE_VERSTAGE && CONFIG(VBOOT_STARTS_IN_BOOTBLOCK))
+	if (ENV_SEPARATE_VERSTAGE && !CONFIG(VBOOT_STARTS_IN_ROMSTAGE))
 		return 0;
 
 	return 1;