Enable APPS SMMU function on QCS615 platform. SMMU is required for
multiple functions including USB/UFS/Ethernet.

The reason of adding scm node:
SMMU driver probe will check qcom_scm ready or not, without scm
node, SMMU driver probe will defer, so add the scm node for SMMU
probe normally.
The dmesg log without scm node:
platform 15000000.iommu: deferred probe pending: arm-smmu: qcom_scm not ready

With the scm node, SMMU can probe normally, but scm driver still fails
to probe because of one scm bug.
The dmesg log of the scm bug:
qcom_scm firmware:scm: error (____ptrval____): Failed to enable the TrustZone memory allocator
qcom_scm firmware:scm: probe with driver qcom_scm failed with error 4
The scm bug mentioned above is fixed:
https://lore.kernel.org/all/20241005140150.4109700-2-quic_kuldsing@quicinc.com/
But above patch to fix scm bug doesn't impact building of current patch series, this
patch series can build successfully without above patch.

Dependency:
https://lore.kernel.org/all/20240926-add_initial_support_for_qcs615-v3-0-e37617e91c62@quicinc.com/

Qingqing Zhou (4):
  dt-bindings: firmware: qcom,scm: document SCM on QCS615
  dt-bindings: arm-smmu: Document Qualcomm QCS615 apps smmu
  arm64: dts: qcom: qcs615: add scm node
  arm64: dts: qcom: qcs615: add the APPS SMMU node

 .../bindings/firmware/qcom,scm.yaml           |  1 +
 .../devicetree/bindings/iommu/arm,smmu.yaml   |  1 +
 arch/arm64/boot/dts/qcom/qcs615.dtsi          | 81 +++++++++++++++++++
 3 files changed, 83 insertions(+)

-- 
2.17.1