src: Drop unused include <timestamp.h>

Change-Id: I7e181111cd1b837382929071a350b94c3afc1aaa
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/31784
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Werner Zeh <werner.zeh@siemens.com>

src/security/vboot/vboot_handoff.c

@@ -31,7 +31,6 @@
 #include <console/vtxprintf.h>
 #include <fmap.h>
 #include <stdlib.h>
-#include <timestamp.h>
 #include <vboot_struct.h>
 #include <security/vboot/vbnv.h>
 #include <security/vboot/misc.h>