dt-bindings: nvmem: add fsl,layerscape-sfp binding

The Security Fuse Processor provides efuses and is responsible for
reading it at SoC startup and configuring it accordingly.
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20220220151527.17216-9-srinivas.kandagatla@linaro.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/nvmem/fsl,layerscape-sfp.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/nvmem/fsl,layerscape-sfp.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Freescale Layerscape Security Fuse Processor
+
+maintainers:
+  - Michael Walle <michael@walle.cc>
+
+description: |
+  SFP is the security fuse processor which among other things provide a
+  unique identifier per part.
+
+allOf:
+  - $ref: "nvmem.yaml#"
+
+properties:
+  compatible:
+    enum:
+      - fsl,ls1028a-sfp
+
+  reg:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    efuse@1e80000 {
+        compatible = "fsl,ls1028a-sfp";
+        reg = <0x1e80000 0x8000>;
+    };