lib: Temporarily remove timestamps from psp_verstage

The timestamp functionality is not yet added for psp_verstage, so
temporarily remove it until that's completed.  That work is being
tracked by bug 154142138.

BUG=b:154142138
TEST=Build & Boot psp_verstage on trembyle

Signed-off-by: Martin Roth <martin@coreboot.org>
Change-Id: I020619e3615ce92dedbe868104d2bfd83cb7caa9
Reviewed-on: https://review.coreboot.org/c/coreboot/+/42381
Reviewed-by: Raul Rangel <rrangel@chromium.org>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/lib/Makefile.inc b/src/lib/Makefile.inc
index e0003bd..72d4f24 100644
--- a/src/lib/Makefile.inc
+++ b/src/lib/Makefile.inc
@@ -46,7 +46,11 @@
 verstage-y += libgcc.c
 verstage-y += memcmp.c
 verstage-y += string.c
+
+# TODO: Remove this when PSP bootblock timestamps are implemented.
+ifeq ($(CONFIG_VBOOT_STARTS_BEFORE_BOOTBLOCK),)
 verstage-$(CONFIG_COLLECT_TIMESTAMPS) += timestamp.c
+endif
 verstage-y += boot_device.c
 verstage-$(CONFIG_CONSOLE_CBMEM) += cbmem_console.c