MAINTAINERS: omap1: Add Janusz as an additional maintainer

Janusz has been active with improving and testing the omap1 SoC support
and has been recently working on adding support for the common clock
framework.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Acked-by: Janusz Krzysztofik <jmkrzyszt@gmail.com>
Acked-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>