dt-bindings: soc: fsl: Add fsl,ls1028a-reset for reset syscon node

ls1028a has a reset module that includes reboot, reset control word, and
service processor control.

Add platform specific compatible string to fix the below warning.

syscon@1e60000: compatible: 'anyOf' conditional failed, one must be fixed:
        ['syscon'] is too short
        'syscon' is not one of ['al,alpine-sysfabric-service', ...]
Signed-off-by: Frank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20240703-ls_reset_syscon-v1-1-338f41b3902d@nxp.comSigned-off-by: Rob Herring (Arm) <robh@kernel.org>

Documentation/devicetree/bindings/soc/fsl/fsl,ls1028a-reset.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas//soc/fsl/fsl,ls1028a-reset.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Freescale Layerscape Reset Registers Module
+
+maintainers:
+  - Frank Li
+
+description:
+  Reset Module includes chip reset, service processor control and Reset Control
+  Word (RCW) status.
+
+properties:
+  $nodename:
+    pattern: "^syscon@[0-9a-f]+$"
+
+  compatible:
+    items:
+      - enum:
+          - fsl,ls1028a-reset
+      - const: syscon
+      - const: simple-mfd
+
+  reg:
+    maxItems: 1
+
+  little-endian: true
+
+  reboot:
+    $ref: /schemas/power/reset/syscon-reboot.yaml#
+    unevaluatedProperties: false
+
+required:
+  - compatible
+  - reg
+  - reboot
+
+additionalProperties: false
+
+examples:
+  - |
+    syscon@1e60000 {
+        compatible = "fsl,ls1028a-reset", "syscon", "simple-mfd";
+        reg = <0x1e60000 0x10000>;
+        little-endian;
+
+        reboot {
+            compatible = "syscon-reboot";
+            offset = <0>;
+            mask = <0x02>;
+        };
+    };
+