dt-bindings: scm: Add compatible for IPQ9574

Add the scm compatible string for IPQ9574 SoC

Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Poovendhan Selvaraj <quic_poovendh@quicinc.com>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230216120012.28357-2-quic_poovendh@quicinc.com