bootstd: Add a bootflow command

Add a 'bootflow' command to handle listing and selection of bootflow.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/cmd/Makefile b/cmd/Makefile
index 474f6d5..addb8f0 100644
--- a/cmd/Makefile
+++ b/cmd/Makefile
@@ -20,6 +20,7 @@
 obj-$(CONFIG_CMD_ARMFLASH) += armflash.o
 obj-$(CONFIG_HAVE_BLOCK_DEVICE) += blk_common.o
 obj-$(CONFIG_CMD_BOOTDEV) += bootdev.o
+obj-$(CONFIG_CMD_BOOTFLOW) += bootflow.o
 obj-$(CONFIG_CMD_SOURCE) += source.o
 obj-$(CONFIG_CMD_BCB) += bcb.o
 obj-$(CONFIG_CMD_BDI) += bdinfo.o