dt-bindings: phy: lynx-28g: add constraint on LX2162A lane indices

The SerDes 1 of LX2162A has fewer lanes than all other instances, and
strangely, their indices are not 0-3, but 4-7.

This is a best-effort constraint, since we can only impose it when using
per-SoC compatible string and per-lane OF nodes.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Tested-by: Josua Mayer <josua@solid-run.com>
Link: https://patch.msgid.link/20260511150023.1903577-3-vladimir.oltean@nxp.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

Documentation/devicetree/bindings/phy/fsl,lynx-28g.yaml

@@ -78,6 +78,21 @@ required:
   - reg
   - "#phy-cells"
 
+allOf:
+  # LX2162A SerDes 1 has fewer lanes than the others
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: fsl,lx2162a-serdes1
+    then:
+      patternProperties:
+        "^phy@[0-7]$":
+          properties:
+            reg:
+              minimum: 4
+              maximum: 7
+
 additionalProperties: false
 
 examples: