dt-bindings: sram: qcom,imem: add IMEM memory region

Add bindings for IMEM memory region (like SRAM) used on several
Qualcomm SoCs.  In the downstream (vendor) tree, it comes with several
children used for debugging purposes.  The upstreamed parts are much
smaller - just image loader and syscon reboot.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220607171848.535128-2-krzysztof.kozlowski@linaro.org

Documentation/devicetree/bindings/sram/qcom,imem.yaml

+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/sram/qcom,imem.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Qualcomm IMEM memory region
+
+maintainers:
+  - Bjorn Andersson <bjorn.andersson@linaro.org>
+
+description:
+  Qualcomm IMEM is dedicated memory region for various debug features and DMA
+  transactions.
+
+properties:
+  compatible:
+    items:
+      - enum:
+          - qcom,apq8064-imem
+          - qcom,msm8974-imem
+          - qcom,qcs404-imem
+          - qcom,sc7180-imem
+          - qcom,sc7280-imem
+          - qcom,sdm630-imem
+          - qcom,sdm845-imem
+          - qcom,sdx55-imem
+      - const: syscon
+      - const: simple-mfd
+
+  reg:
+    maxItems: 1
+
+  ranges: true
+
+  '#address-cells':
+    const: 1
+
+  '#size-cells':
+    const: 1
+
+  reboot-mode:
+    $ref: /schemas/power/reset/syscon-reboot-mode.yaml#
+
+patternProperties:
+  "^pil-reloc@[0-9a-f]+$":
+    $ref: /schemas/remoteproc/qcom,pil-info.yaml#
+    description: Peripheral image loader relocation region
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    soc {
+        #address-cells = <2>;
+        #size-cells = <2>;
+
+        sram@146bf000 {
+            compatible = "qcom,sdm845-imem", "syscon", "simple-mfd";
+            reg = <0 0x146bf000 0 0x1000>;
+            ranges = <0 0 0x146bf000 0x1000>;
+
+            #address-cells = <1>;
+            #size-cells = <1>;
+
+            pil-reloc@94c {
+                compatible = "qcom,pil-reloc-info";
+                reg = <0x94c 0xc8>;
+            };
+        };
+    };