dt-bindings: gnss: Rewrite Mediatek bindings in YAML

This rewrites the Mediatek GNSS bindings in YAML.

Cc: devicetree@vger.kernel.org
Cc: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220425132947.1311171-1-linus.walleij@linaro.org