toradex: hand over maintainership

Hand over maintainership of Toradex SoMs (that I was responsible of) to
Oleksandr because of my resignation from Toradex, as such I will
have no immediate involvement with these modules and as a result not
able to continue maintaining these boards.

CC: Oleksandr Suvorov <oleksandr.suvorov@toradex.com>
Signed-off-by: Igor Opaniuk <igor.opaniuk@toradex.com>
Reviewed-by: Oleksandr Suvorov <oleksandr.suvorov@toradex.com>
Acked-by: Oleksandr Suvorov <oleksandr.suvorov@toradex.com>