board: gateworks: venice: move README to RST

Move board/gateworks/venice/README to RST documentation.

Signed-off-by: Tim Harvey <tharvey@gateworks.com>
diff --git a/board/gateworks/venice/MAINTAINERS b/board/gateworks/venice/MAINTAINERS
index cfdea0c..01a47a1 100644
--- a/board/gateworks/venice/MAINTAINERS
+++ b/board/gateworks/venice/MAINTAINERS
@@ -3,5 +3,6 @@
 S:	Maintained
 F:	arch/arm/dts/imx8m*-venice*
 F:	board/gateworks/venice/
+F:	doc/board/gateworks/*venice*
 F:	include/configs/imx8m*_venice.h
 F:	configs/imx8m*_venice_defconfig