dt-bindings: mtd/partitions: Convert arm-firmware-suite to DT schema

Convert the arm,arm-firmware-suite partition binding to DT schema
format. Simple conversion as there's only a compatible property.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/r/20220629185031.23826-1-robh@kernel.org

Documentation/devicetree/bindings/mtd/partitions/arm,arm-firmware-suite.txt

-ARM AFS - ARM Firmware Suite Partitions
-=======================================
-
-The ARM Firmware Suite is a flash partitioning system found on the
-ARM reference designs: Integrator AP, Integrator CP, Versatile AB,
-Versatile PB, the RealView family, Versatile Express and Juno.
-
-Required properties:
-- compatible : (required) must be "arm,arm-firmware-suite"
-
-Example:
-
-flash@0 {
-	partitions {
-		compatible = "arm,arm-firmware-suite";
-	};
-};

Documentation/devicetree/bindings/mtd/partitions/arm,arm-firmware-suite.yaml

+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mtd/partitions/arm,arm-firmware-suite.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: ARM Firmware Suite (AFS) Partitions
+
+maintainers:
+  - Linus Walleij <linus.walleij@linaro.org>
+
+description: |
+  The ARM Firmware Suite is a flash partitioning system found on the
+  ARM reference designs: Integrator AP, Integrator CP, Versatile AB,
+  Versatile PB, the RealView family, Versatile Express and Juno.
+
+properties:
+  compatible:
+    const: arm,arm-firmware-suite
+
+additionalProperties: false
+
+examples:
+  - |
+    partitions {
+        compatible = "arm,arm-firmware-suite";
+    };
+...