dt-bindings/perf: Add Arm NI-700 PMU

Add an initial binding for the Arm NI-700 interconnect PMU. As with the
Arm CMN family, there are already future NI products on the roadmap, so
the overall binding is named generically just in case any
non-discoverable incompatibility between generations crops up.

Cc: [e-mail]
Reviewed-by: Rob Herring (Arm) <[e-mail]>
Signed-off-by: Robin Murphy <[e-mail]>
Link: https://lore.kernel.org/r/5f86[e-mail]
Signed-off-by: Will Deacon <[e-mail]>

Documentation/devicetree/bindings/perf/arm,ni.yaml

···
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/perf/arm,ni.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Arm NI (Network-on-Chip Interconnect) Performance Monitors
+
+maintainers:
+  - Robin Murphy <[e-mail]>
+
+properties:
+  compatible:
+    const: arm,ni-700
+
+  reg:
+    items:
+      - description: Complete configuration register space
+
+  interrupts:
+    minItems: 1
+    maxItems: 32
+    description: Overflow interrupts, one per clock domain, in order of domain ID
+
+required:
+  - compatible
+  - reg
+  - interrupts
+
+additionalProperties: false