dt-bindings: arm: qcom: add missing SDM636 board compatibles

Document board compatibles already present in Linux kernel.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220521164550.91115-6-krzysztof.kozlowski@linaro.org


Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>