dt-bindings: iio: dac: change ad3552r maintainer

As the maintainer email no longer exists, change it to myself.
Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220404085000.249423-2-nuno.sa@analog.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/devicetree/bindings/iio/dac/adi,ad3552r.yaml

@@ -8,7 +8,7 @@ $schema: http://devicetree.org/meta-schemas/core.yaml#
 title: Analog Devices AD2552R DAC device driver
 
 maintainers:
-  - Mihail Chindris <mihail.chindris@analog.com>
+  - Nuno Sá <nuno.sa@analog.com>
 
 description: |
   Bindings for the Analog Devices AD3552R DAC device and similar.