dt-bindings: mfd: atmel,at91sam9260: Convert to YAML schema

Changes during conversion:

Add a missing fallback `atmel,at91sam9x5-matrix` for
`microchip,sam9x60-matrix` which is not defined in the text binding.

Signed-off-by: Charan Pedumuru <charan.pedumuru@microchip.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20241218-matrix-v2-1-f3a8809ee5cd@microchip.com
Signed-off-by: Lee Jones <lee@kernel.org>

Documentation/devicetree/bindings/mfd/atmel,at91sam9260-matrix.yaml

@@ -0,0 +1,52 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mfd/atmel,at91sam9260-matrix.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Microchip AT91 Bus Matrix
+
+maintainers:
+  - Nicolas Ferre <nicolas.ferre@microchip.com>
+
+description:
+  The Bus Matrix (MATRIX) implements a multi-layer AHB, based on the
+  AHB-Lite protocol, that enables parallel access paths between multiple
+  masters and slaves in a system, thus increasing the overall bandwidth.
+
+properties:
+  compatible:
+    oneOf:
+      - items:
+          - enum:
+              - atmel,at91sam9260-matrix
+              - atmel,at91sam9261-matrix
+              - atmel,at91sam9263-matrix
+              - atmel,at91sam9rl-matrix
+              - atmel,at91sam9g45-matrix
+              - atmel,at91sam9n12-matrix
+              - atmel,at91sam9x5-matrix
+              - atmel,sama5d3-matrix
+          - const: syscon
+      - items:
+          - enum:
+              - microchip,sam9x60-matrix
+              - microchip,sam9x7-matrix
+          - const: atmel,at91sam9x5-matrix
+          - const: syscon
+
+  reg:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    syscon@ffffec00 {
+        compatible = "atmel,sama5d3-matrix", "syscon";
+        reg = <0xffffec00 0x200>;
+    };