Convert CONFIG_SCSI to Kconfig

This converts the following to Kconfig:
   CONFIG_SCSI

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/arch/Kconfig b/arch/Kconfig
index fe1b991..8d5d77a 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -75,6 +75,7 @@
 	imply FAT_WRITE
 	imply HASH_VERIFY
 	imply LZMA
+	imply SCSI
 
 config SH
 	bool "SuperH architecture"