build system/x86: depend on directories before touch /empty targets

$(objgenerated)/empty would touch files before the directory
is created on parallel builds.

Thanks to reproducible-builds.org for hitting this bug.

Change-Id: I7565e9fe130b4e9deaf1c7b9d568ff90b00dda52
Signed-off-by: Alexander Couzens <lynxis@fe80.eu>
Reviewed-on: https://review.coreboot.org/12717
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

0 files changed, 0 insertions, 0 deletions