When PciBus is built as EBC, PcdPciDegradeResourceForOptionRom does not have associated value resulting build failure. The patch sets the default value to TRUE, covering the EBC ARCH. Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com> Acked-by: Laszlo Ersek <lersek@redhat.com> Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Reviewed-by: Feng Tian <feng.tian@intel.com>