doc: Move bootstd into its own directory

Before adding more files, move the bootstd docs into a new directory,
with an index.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Quentin Schulz <quentin.schulz@cherry.de>
Reviewed-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
diff --git a/doc/develop/board_best_practices.rst b/doc/develop/board_best_practices.rst
index f44401e..09632c8 100644
--- a/doc/develop/board_best_practices.rst
+++ b/doc/develop/board_best_practices.rst
@@ -7,7 +7,7 @@
 following the :doc:`docstyle` and the :doc:`codingstyle` there are some things
 which are specific to creating a new board port.
 
-* Implement :doc:`bootstd` to ensure that most operating systems will be
+* Implement :doc:`bootstd/index` to ensure that most operating systems will be
   supported by the platform.
 
 * The platform defconfig file must be generated via `make savedefconfig`.
diff --git a/doc/develop/bootstd/index.rst b/doc/develop/bootstd/index.rst
new file mode 100644
index 0000000..f4f87c7
--- /dev/null
+++ b/doc/develop/bootstd/index.rst
@@ -0,0 +1,9 @@
+.. SPDX-License-Identifier: GPL-2.0+:
+
+Standard Boot
+=============
+
+.. toctree::
+   :maxdepth: 2
+
+   overview
diff --git a/doc/develop/bootstd.rst b/doc/develop/bootstd/overview.rst
similarity index 98%
rename from doc/develop/bootstd.rst
rename to doc/develop/bootstd/overview.rst
index bdda90f..aa38ad9 100644
--- a/doc/develop/bootstd.rst
+++ b/doc/develop/bootstd/overview.rst
@@ -1,7 +1,7 @@
 .. SPDX-License-Identifier: GPL-2.0+:
 
-U-Boot Standard Boot
-====================
+Standard Boot Overview
+======================
 
 Introduction
 ------------
@@ -17,7 +17,7 @@
 For Linux, the distro (Linux distribution, e.g. Debian, Fedora) is responsible
 for creating a bootflow for each kernel combination that it wants to offer.
 These bootflows are stored on media so they can be discovered by U-Boot. This
-feature is typically called `distro boot` (see :doc:`distro`) because it is
+feature is typically called `distro boot` (see :doc:`../distro`) because it is
 a way for distributions to boot on any hardware.
 
 Traditionally U-Boot has relied on scripts to implement this feature. See
@@ -32,7 +32,7 @@
 Systems (such as Chromium OS) and devices (beyond just block and network
 devices). It supports EFI boot and EFI bootmgr too.
 
-Finally, standard boot supports the operation of :doc:`vbe`.
+Finally, standard boot supports the operation of :doc:`../vbe`.
 
 Bootflow
 --------
@@ -432,16 +432,16 @@
 
 `bootdev`
     Allows listing of available bootdevs, selecting a particular one and
-    getting information about it. See :doc:`../usage/cmd/bootdev`
+    getting information about it. See :doc:`/usage/cmd/bootdev`
 
 `bootflow`
     Allows scanning one or more bootdevs for bootflows, listing available
     bootflows, selecting one, obtaining information about it and booting it.
-    See :doc:`../usage/cmd/bootflow`
+    See :doc:`/usage/cmd/bootflow`
 
 `bootmeth`
     Allow listing of available bootmethds and setting the order in which they
-    are tried. See :doc:`../usage/cmd/bootmeth`
+    are tried. See :doc:`/usage/cmd/bootmeth`
 
 .. _BootflowStates:
 
diff --git a/doc/develop/index.rst b/doc/develop/index.rst
index f9c4bf8..c0107a7 100644
--- a/doc/develop/index.rst
+++ b/doc/develop/index.rst
@@ -29,7 +29,7 @@
 
    directories
    bloblist
-   bootstd
+   bootstd/index
    ci_testing
    commands
    config_binding