MAINTAINERS: ARM: moxa: add Krzysztof Kozlowski as maintainer

There is no maintainers entry for the ARM MOXA ART SoC, thus patches end
up nowhere.  Add such entry, because even if platform is orphaned and on
its way out of the kernel, it is nice to take patches if someone sends
something.

I do not plan to actively support/maintain MOXA but I can take odd fixes
now and then.

Cc: Jonas Jensen <jonas.jensen@gmail.com>
Link: https://lore.kernel.org/r/20240613135956.8899-1-krzysztof.kozlowski@linaro.org


Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>