dt-bindings: net: ftgmac100: convert to yaml version from txt

Conversion from ftgmac100.txt to yaml format version.

Signed-off-by: Ivan Mikhaylov <fr0st61te@gmail.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230805135318.6102-1-fr0st61te@gmail.com


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