board: amlogic: add mailing-list to MAINTAINERS

Add missing mailing-list to the amlogic boards MAINTAINERS file.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
diff --git a/board/amlogic/p201/MAINTAINERS b/board/amlogic/p201/MAINTAINERS
index 3e84a8e..f84984d 100644
--- a/board/amlogic/p201/MAINTAINERS
+++ b/board/amlogic/p201/MAINTAINERS
@@ -1,5 +1,6 @@
 P201
 M:	Neil Armstrong <narmstrong@baylibre.com>
 S:	Maintained
+L:	u-boot-amlogic@groups.io
 F:	board/amlogic/p201/
 F:	configs/p201_defconfig