dt-bindings: i3c: mipi-hci: Include the bus binding

Update a little bit the content to match the bus binding, including:
- the node title should have been named after the description done
  in the historical i3c.txt file, ie: i3c-master@<address>
- child nodes should be accepted even though the drivers do not currently
  support it
- #address-cells and #size-cells are also mandatory and have specific
  values

Cc: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20210121101808.14654-3-miquel.raynal@bootlin.com

Documentation/devicetree/bindings/i3c/mipi-i3c-hci.yaml

@@ -9,6 +9,9 @@ title: MIPI I3C HCI Device Tree Bindings
 maintainers:
   - Nicolas Pitre <npitre@baylibre.com>
 
+allOf:
+  - $ref: /schemas/i3c/i3c.yaml#
+
 description: |
   MIPI I3C Host Controller Interface
 
@@ -36,12 +39,14 @@ required:
   - reg
   - interrupts
 
-additionalProperties: false
+unevaluatedProperties: false
 
 examples:
   - |
-    i3c@a0000000 {
+    i3c-master@a0000000 {
       compatible = "mipi-i3c-hci";
       reg = <0xa0000000 0x2000>;
       interrupts = <89>;
+      #address-cells = <3>;
+      #size-cells = <0>;
     };