dt-bindings: firmware: scm: Add compatible for msm8226

Add devicetree compatible for SCM present in msm8226 platform.
Signed-off-by: NLuca Weiss <luca@z3ntu.xyz>
Signed-off-by: NBjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20210911232707.259615-4-luca@z3ntu.xyz

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

@@ -13,6 +13,7 @@ Required properties:
  * "qcom,scm-ipq806x"
  * "qcom,scm-ipq8074"
  * "qcom,scm-mdm9607"
+ * "qcom,scm-msm8226"
  * "qcom,scm-msm8660"
  * "qcom,scm-msm8916"
  * "qcom,scm-msm8960"