ARM: dts: msm: Define adsp_mem_heap region

Define adsp mem heap region for adsp-mem device. Also
add documentation for the same.

Change-Id: Icce88b87c28797ff51ba5b0d885706d3a903eee3
Signed-off-by: Anirudh Raghavendra <quic_araghave@quicinc.com>

bindings/qdsp/msm-fastrpc.yaml

@@ -0,0 +1,33 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/qdsp/msm-fastrpc.yaml#"
+$schema: "http://devicetree.org/meta-schemas/core.yaml#"
+
+title: ADSP remote heap region
+
+description:
+  Defines the ADSP remote heap region. Device used for CMA allocations
+  and mappings for both secure and non-secure usecases.
+
+maintainers:
+  - Anirudh Raghavendra <quic_araghave@quicinc.com>
+
+properties:
+  compatible:
+    const: qcom,adsprpc-mem
+
+required:
+  - compatible
+  - memory-region
+  - restrict-access
+
+additionalProperties: false
+
+examples:
+  - |
+    qcom,adsprpc-mem {
+      compatible = "qcom,msm-adsprpc-mem-region";
+      memory-region = <&adsp_mem>;
+      restrict-access;
+    };