In order to add more option backends, transform the current CMOS option
backend into a Kconfig choice. Replace the `select` directives, as they
cannot be used with choice options.
Change-Id: Id3180e9991f0e763b4bae93a92d40668e7fc99bc
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/54728
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
17852e61df