bootstd: Add a SCSI bootdev

Add a bootdev for SCSI so that these devices can be used with standard
boot.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/scsi/Makefile b/drivers/scsi/Makefile
index d1b40c6..d8d6de5 100644
--- a/drivers/scsi/Makefile
+++ b/drivers/scsi/Makefile
@@ -6,6 +6,13 @@
 ifndef CONFIG_SPL_BUILD
 obj-$(CONFIG_DM_SCSI) += scsi-uclass.o
 obj-$(CONFIG_SCSI) += scsi.o
+
+ifdef CONFIG_SCSI
+ifdef CONFIG_DM_SCSI
+obj-$(CONFIG_$(SPL_TPL_)BOOTSTD) += scsi_bootdev.o
+endif
+endif
+
 endif
 
 ifdef CONFIG_SPL_BUILD