toradex: take over maintainership

Also take over maintainership of remaining Toradex SoMs as Oleksandr
has left our company.

Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
CC: Oleksandr Suvorov <cryosay@gmail.com>
diff --git a/board/toradex/colibri-imx6ull/MAINTAINERS b/board/toradex/colibri-imx6ull/MAINTAINERS
index 899b1ff..eb491c2 100644
--- a/board/toradex/colibri-imx6ull/MAINTAINERS
+++ b/board/toradex/colibri-imx6ull/MAINTAINERS
@@ -1,5 +1,5 @@
 Colibri iMX6ULL
-M:	Oleksandr Suvorov <oleksandr.suvorov@toradex.com>
+M:	Marcel Ziswiler <marcel.ziswiler@toradex.com>
 W:	http://developer.toradex.com/software/linux/linux-software
 W:	https://www.toradex.com/community
 S:	Maintained