dt-bindings: firmware: scm: Add compatible for SDX55

Add devicetree compatible for SCM present in SDX55 platform.
Acked-by: Rob Herring <robh@kernel.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: devicetree@vger.kernel.org
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20210408170457.91409-7-manivannan.sadhasivam@linaro.orgSigned-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

Documentation/devicetree/bindings/firmware/qcom,scm.txt

@@ -21,6 +21,7 @@ Required properties:
  * "qcom,scm-msm8998"
  * "qcom,scm-sc7180"
  * "qcom,scm-sdm845"
+ * "qcom,scm-sdx55"
  * "qcom,scm-sm8150"
  * "qcom,scm-sm8250"
  * "qcom,scm-sm8350"