arm64: defconfig: Enable support for cbmem entries in the coreboot table

Enable the cbmem driver and dependencies in order to support reading
cbmem entries from the coreboot table, which are used to store logs from
coreboot on arm64 Chromebooks, and provide useful information for
debugging the boot process on those devices.

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Link: https://lore.kernel.org/r/20240304-coreboot-defconfig-v1-1-02dc1940408f@collabora.com


Signed-off-by: Arnd Bergmann <arnd@arndb.de>