dt-bindings: firmware: document Qualcomm QCS404 and SM6125 SCM

Document the compatible for Qualcomm QCS404 and SM6125 SCM.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220622115109.6724-1-krzysztof.kozlowski@linaro.org