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/board/tbs/tbs2910/MAINTAINERS b/board/tbs/tbs2910/MAINTAINERS
index a3ad2f7..1e3c0d0 100644
--- a/board/tbs/tbs2910/MAINTAINERS
+++ b/board/tbs/tbs2910/MAINTAINERS
@@ -4,4 +4,5 @@
 F:	arch/arm/dts/imx6q-tbs2910.dts
 F:	board/tbs/tbs2910/
 F:	configs/tbs2910_defconfig
+F:	doc/board/tbs/
 F:	include/configs/tbs2910.h