Cache the found microcode for faster subsequent accesses. Change-Id: Ic40d57964600f8f20ddb26c7d1691b043fd89f29 Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com> Reviewed-on: https://review.coreboot.org/c/coreboot/+/49896 Reviewed-by: Angel Pons <th3fanbus@gmail.com> Reviewed-by: Arthur Heymans <arthur@aheymans.xyz> Tested-by: build bot (Jenkins) <no-reply@coreboot.org>