dt-bindings: i2c: renesas,riic: Move ref for i2c-controller.yaml to the end

In preparation for adding more validation checks, move the `$ref` for
'i2c-controller.yaml' to the end of the file. Also, relocate the
conditional check for 'resets' into the 'allOf' block.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Link: https://lore.kernel.org/r/20250625104526.101004-2-prabhakar.mahadev-lad.rj@bp.renesas.com

Documentation/devicetree/bindings/i2c/renesas,riic.yaml

@@ -10,9 +10,6 @@ maintainers:
   - Chris Brandt <chris.brandt@renesas.com>
   - Wolfram Sang <wsa+renesas@sang-engineering.com>
 
-allOf:
-  - $ref: /schemas/i2c/i2c-controller.yaml#
-
 properties:
   compatible:
     oneOf:
@@ -84,18 +81,21 @@ required:
   - '#address-cells'
   - '#size-cells'
 
-if:
-  properties:
-    compatible:
-      contains:
-        enum:
-          - renesas,riic-r9a07g043
-          - renesas,riic-r9a07g044
-          - renesas,riic-r9a07g054
-          - renesas,riic-r9a09g057
-then:
-  required:
-    - resets
+allOf:
+  - $ref: /schemas/i2c/i2c-controller.yaml#
+
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - renesas,riic-r9a07g043
+              - renesas,riic-r9a07g044
+              - renesas,riic-r9a07g054
+              - renesas,riic-r9a09g057
+    then:
+      required:
+        - resets
 
 unevaluatedProperties: false