doc: boards: amlogic: add documentation for Beelink GT1 Ultimate

Add build instructions for the Beelink GT1 Ultimate board.

Signed-off-by: Christian Hewitt <christianshewitt@gmail.com>
Signed-off-by: Karl Chan <exxxxkc@getgoogleoff.me>
Link: https://lore.kernel.org/r/8760391a-3506-5ac5-8d55-92c23cccff44@yahoo.com
[narmstrong: fixed MAINTAINERS indentation, added doc to index]
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
diff --git a/board/amlogic/q200/MAINTAINERS b/board/amlogic/q200/MAINTAINERS
index 9c84cca..aece8d5 100644
--- a/board/amlogic/q200/MAINTAINERS
+++ b/board/amlogic/q200/MAINTAINERS
@@ -4,9 +4,11 @@
 L:	u-boot-amlogic@groups.io
 F:	board/amlogic/q200/
 F:	include/configs/q200.h
+F:	configs/beelink-gt1-ultimate_defconfig
 F:	configs/khadas-vim2_defconfig
 F:	configs/libretech-s905d-pc_defconfig
 F:	configs/libretech-s912-pc_defconfig
 F:	configs/wetek-core2_defconfig
+F:	doc/board/amlogic/beelink-gt1-ultimate.rst
 F:	doc/board/amlogic/khadas-vim2.rst
 F:	doc/board/amlogic/wetek-core2.rst