dt-bindings: firmware: qcom-scm: Document msm8976 bindings

SCM driver on MSM8976 requires 3 clocks.
Signed-off-by: Adam Skladowski <a39.skl@gmail.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220307191726.10869-4-a39.skl@gmail.com

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

@@ -19,6 +19,7 @@ Required properties:
  * "qcom,scm-msm8953"
  * "qcom,scm-msm8960"
  * "qcom,scm-msm8974"
+ * "qcom,scm-msm8976"
  * "qcom,scm-msm8994"
  * "qcom,scm-msm8996"
  * "qcom,scm-msm8998"
@@ -37,7 +38,7 @@ Required properties:
  * core clock required for "qcom,scm-apq8064", "qcom,scm-msm8660" and
    "qcom,scm-msm8960"
  * core, iface and bus clocks required for "qcom,scm-apq8084",
-   "qcom,scm-msm8916", "qcom,scm-msm8953" and "qcom,scm-msm8974"
+   "qcom,scm-msm8916", "qcom,scm-msm8953", "qcom,scm-msm8974" and "qcom,scm-msm8976"
 - clock-names: Must contain "core" for the core clock, "iface" for the interface
   clock and "bus" for the bus clock per the requirements of the compatible.
 - qcom,dload-mode: phandle to the TCSR hardware block and offset of the