x86: Switch all boards to use DM SCSI

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>
diff --git a/arch/Kconfig b/arch/Kconfig
index fdcf7cd..e063ee0 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -95,12 +95,14 @@
 	select PCI
 	select TIMER
 	select X86_TSC_TIMER
+	imply BLK
 	imply DM_ETH
 	imply DM_GPIO
 	imply DM_KEYBOARD
 	imply DM_MMC
 	imply DM_RTC
 	imply DM_SERIAL
+	imply DM_SCSI
 	imply DM_SPI
 	imply DM_SPI_FLASH
 	imply DM_USB