arch/x86: Include acpi_s3.c support in postcar stage

This patch ensures acpi APIs are available for postcar
stage.

Change-Id: Ia0f83cd4886ba7a16286dbbeb3257ede014ee3c7
Signed-off-by: Subrata Banik <subrata.banik@intel.com>
Reviewed-on: https://review.coreboot.org/21626
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
2 files changed