board: amlogic: add board doc files to MAINTAINERS

Add the recently added reStructuredText board documentation in the
appropriate MAINTAINERS files.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
diff --git a/MAINTAINERS b/MAINTAINERS
index 00985c0..db8cecd 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -145,6 +145,7 @@
 F:	drivers/video/meson/
 F:	include/configs/meson64.h
 F:	include/configs/meson64_android.h
+F:	doc/board/amlogic/
 N:	meson
 
 ARM BROADCOM BCM283X