dt-bindings: net: cdns,macb: use correct xlnx prefix for Xilinx

dt-bindings: net: cdns,macb: use correct xlnx prefix for Xilinx

Use correct vendor for Xilinx versions of Cadence MACB/GEM Ethernet
controller.  The Versal compatible was not released, so it can be
changed.  Zynq-7xxx and Ultrascale+ has to be kept in new and deprecated
form.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220726070802.26579-1-krzysztof.kozlowski@linaro.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>