dt-bindings: gnss: Rewrite sirfstar binding in YAML

This rewrites the SiRFstar DT bindings in YAML.

Cc: devicetree@vger.kernel.org
Cc: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220317225844.1262643-3-linus.walleij@linaro.org