dt-bindings: xilinx: Remove Naga from memory and mtd bindings

Naga is no longer works for AMD/Xilinx and there is no activity from him to
continue to maintain Xilinx related drivers. Two drivers have Miquel as
maintainer and for the last one add myself instead to be kept in a loop if
there is any change required.

Signed-off-by: Michal Simek <michal.simek@amd.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/6b4cdc7158599b4a38409a03eda56e38975b6233.1683103250.git.michal.simek@amd.com


Signed-off-by: Rob Herring <robh@kernel.org>