still not fixing things properly but at least it should now be possible to build older thinkpads without regressions.
prior, some code was just commented or unreachable. now we make this explicit with preprocessor directives.
heads should build all boards on this coreboot version from the same coreboot tree.
use CONFIG_BOARD_LENOVO_SKLKBL_THINKPAD_COMMON to decide what to compile
this should work for T480, T480S and older thinkpads
Signed-off-by: gaspar-ilom <gasparilom@riseup.net>
3466272a69