board/km: update MAINTAINERS email

Signed-off-by: Holger Brunck <holger.brunck@hitachi-powergrids.com>
CC: Valentin Longchamp <valentin.longchamp@hitachi-powergrids.com>
diff --git a/board/keymile/km_arm/MAINTAINERS b/board/keymile/km_arm/MAINTAINERS
index 3eeb509..8da58da 100644
--- a/board/keymile/km_arm/MAINTAINERS
+++ b/board/keymile/km_arm/MAINTAINERS
@@ -1,5 +1,5 @@
 KM_ARM BOARD
-M:	Valentin Longchamp <valentin.longchamp@ch.abb.com>
+M:	Valentin Longchamp <valentin.longchamp@hitachi-powergrids.com>
 S:	Maintained
 F:	board/keymile/km_arm/
 F:	include/configs/km_kirkwood.h