dt-bindings: arm: qcom: Document huawei,sturgeon device

Document the Huawei Watch ("sturgeon") which is a smartwatch based on
Snapdragon 400 SoC.

Signed-off-by: Luca Weiss <luca@z3ntu.xyz>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20220924152937.4076-1-luca@z3ntu.xyz