MAINTAINERS: Add Krzysztof Kozlowski to Samsung S3FWRN5 and remove Robert

Robert Bałdyga's email does not work (bounces) since 2016 so remove it.
Additionally there are no review/ack/tested tags from Krzysztof Opasiak
so it looks like the driver is not supported.

As a maintainer of Samsung ARM/ARM64 SoC, I can take care about this
driver and provide some review.  However clearly driver is not in
supported mode as I do not work in Samsung anymore.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>