MAINTAINERS: Update email of Neil Armstrong

My professional e-mail will change and the BayLibre one will
bounce after mid-september of 2022.

This updates the MAINTAINERS files and adds an entry in the
.mailmap file.

Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
diff --git a/board/amlogic/s400/MAINTAINERS b/board/amlogic/s400/MAINTAINERS
index fb46b1b..ca51bb6 100644
--- a/board/amlogic/s400/MAINTAINERS
+++ b/board/amlogic/s400/MAINTAINERS
@@ -1,5 +1,5 @@
 S400
-M:	Neil Armstrong <narmstrong@baylibre.com>
+M:	Neil Armstrong <neil.armstrong@linaro.org>
 S:	Maintained
 L:	u-boot-amlogic@groups.io
 F:	board/amlogic/s400/