board: tbs2910: add documentation

This documents the u-boot installation procedure and the
hardware in order to get started.

Signed-off-by: Denis 'GNUtoo' Carikli <GNUtoo@cyberdimension.org>
[trini: Add MAINTAINERS entry for doc file per Soeren's request]
diff --git a/doc/board/tbs/index.rst b/doc/board/tbs/index.rst
new file mode 100644
index 0000000..b677bc6
--- /dev/null
+++ b/doc/board/tbs/index.rst
@@ -0,0 +1,9 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+TBS
+===
+
+.. toctree::
+   :maxdepth: 2
+
+   tbs2910