src: Use '#include <timestamp.h>' when needed

Change-Id: Ic0483982e8115ae99367d08d8ed77b8a316f5405
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/34231
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>

src/lib/decompressor.c

@@ -19,6 +19,7 @@
 #include <delay.h>
 #include <program_loading.h>
 #include <symbols.h>
+#include <timestamp.h>
 
 extern u8 compressed_bootblock[];
 asm (