mb/purism/librem_skl: select DRIVERS_GENERIC_CBFS_SERIAL

This driver was previously added for another out-of-tree Librem device, but
forgot to switch over the librem_skl boards to use it. Remove
duplicate functionality from mainboard.c and delete the empty file.

Test: build/boot Librem 13v2 and verify serial number read from CBFS
via dmidecode.

Signed-off-by: Matt DeVillier <matt.devillier@puri.sm>
Change-Id: Ide952197335c6bfbad846c6d6f62be5c4c57e2cb
Reviewed-on: https://review.coreboot.org/c/coreboot/+/41040
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

0 files changed, 0 insertions, 0 deletions