After MMC is converted to DM, convert to use DM SCSI as well for all
x86 boards and imply BLK for both MMC and SCSI drivers.
CONFIG_SCSI_DEV_LIST is no longer used. Clean them up.
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>