dt-bindings: arm: spe-pmu: convert to DT schema

Convert the Arm Statisical Profiling Extension (SPE) binding to DT
schema.
Not much to see here, basically just the announcement that SPE is
integrated on the system level and where the IRQ is routed to.

Move it into the more suitable perf/ directory on the way.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220506140533.3566431-3-andre.przywara@arm.com

Documentation/devicetree/bindings/arm/spe-pmu.txt

-* ARMv8.2 Statistical Profiling Extension (SPE) Performance Monitor Units (PMU)
-
-ARMv8.2 introduces the optional Statistical Profiling Extension for collecting
-performance sample data using an in-memory trace buffer.
-
-** SPE Required properties:
-
-- compatible : should be one of:
-	       "arm,statistical-profiling-extension-v1"
-
-- interrupts : Exactly 1 PPI must be listed. For heterogeneous systems where
-               SPE is only supported on a subset of the CPUs, please consult
-	       the arm,gic-v3 binding for details on describing a PPI partition.
-
-** Example:
-
-spe-pmu {
-        compatible = "arm,statistical-profiling-extension-v1";
-        interrupts = <GIC_PPI 05 IRQ_TYPE_LEVEL_HIGH &part1>;
-};

Documentation/devicetree/bindings/perf/spe-pmu.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/perf/spe-pmu.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: ARMv8.2 Statistical Profiling Extension (SPE) Performance Monitor Units (PMU)
+
+maintainers:
+  - Will Deacon <will@kernel.org>
+
+description:
+  ARMv8.2 introduces the optional Statistical Profiling Extension for collecting
+  performance sample data using an in-memory trace buffer.
+
+properties:
+  compatible:
+    const: arm,statistical-profiling-extension-v1
+
+  interrupts:
+    maxItems: 1
+    description: |
+      The PPI to signal SPE events. For heterogeneous systems where SPE is only
+      supported on a subset of the CPUs, please consult the arm,gic-v3 binding
+      for details on describing a PPI partition.
+
+additionalProperties: false
+
+required:
+  - compatible
+  - interrupts
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+
+    spe-pmu {
+        compatible = "arm,statistical-profiling-extension-v1";
+        interrupts = <GIC_PPI 5 IRQ_TYPE_LEVEL_HIGH>;
+    };