Use microcode updates from intel-microcode submodule by default.
Downstream users can still decide to use their own files.
TEST=Build and boot on intel/avenuecity CRB
TEST=Build and boot on intel/beechnutcity CRB
Change-Id: I5a37423426b19dc9ec76984df5ad9c6d2a28f83b
Signed-off-by: Jincheng Li <jincheng.li@intel.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/88283
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Shuo Liu <shuo.liu@intel.com>