bootstd: doc: Add documentation

Add documentation for this feature, including the commands and full
devicetree bindings.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/doc/usage/index.rst b/doc/usage/index.rst
index f343e4e..c03f4ae 100644
--- a/doc/usage/index.rst
+++ b/doc/usage/index.rst
@@ -23,9 +23,12 @@
    cmd/addrmap
    cmd/askenv
    cmd/base
+   cmd/bootdev
    cmd/bootefi
+   cmd/bootflow
    cmd/booti
    cmd/bootmenu
+   cmd/bootmeth
    cmd/button
    cmd/cbsysinfo
    cmd/conitrace