dt-bindings: pinctrl: rt2880: properly redo bindings

When this bindings where applied there weren't already
reviewed and some old hacks was being used to properly
pass the schemas checks. This commits fix them up:
 - Instead of using 'if-then' clause use '-pins$'.
 - 'groups' and 'function' are included inside a new
   '^(.*-)?pinmux$' node.
 - compatible string is not an 'enum' but a 'const'.
 - 'pinctrl-0' and 'pinctrl-names' removed since they are
    used in consumer nodes.

Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20201213161721.6514-2-sergio.paracuellos@gmail.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Documentation/devicetree/bindings/pinctrl/ralink,rt2880-pinmux.yaml

@@ -15,39 +15,38 @@ description:
 
 properties:
   compatible:
-    enum:
+    const: ralink,rt2880-pinmux
-      - ralink,rt2880-pinmux
 
-  pinctrl-0:
+patternProperties:
-    description:
+  '-pins$':
-      A phandle to the node containing the subnodes containing default
+    type: object
-      configurations. This is for pinctrl hogs.
+    patternProperties:
+      '^(.*-)?pinmux$':
+        type: object
+        description: node for pinctrl.
+        $ref: pinmux-node.yaml#
 
-  pinctrl-names:
+        properties:
-    description:
+          groups:
-      A pinctrl state named "default" can be defined.
+            description: Name of the pin group to use for the functions.
-    const: default
+            enum: [i2c, spi, uart1, uart2, uart3, rgmii1, rgmii2, mdio,
+                   pcie, sdhci]
+          function:
+            description: The mux function to select
+            enum: [gpio, i2c, spi, uart1, uart2, uart3, rgmii1, rgmii2,
+                   mdio, nand1, nand2, sdhci]
+
+        required:
+          - groups
+          - function
+
+        additionalProperties: false
+
+    additionalProperties: false
 
 required:
   - compatible
 
-patternProperties:
-  '[a-z0-9_-]+':
-    if:
-      type: object
-      description: node for pinctrl.
-      $ref: "pinmux-node.yaml"
-    then:
-      properties:
-        groups:
-          description: Name of the pin group to use for the functions.
-          enum: [i2c, spi, uart1, uart2, uart3, rgmii1, rgmii2, mdio,
-                 pcie, sdhci]
-        function:
-          description: The mux function to select
-          enum: [gpio, i2c, spi, uart1, uart2, uart3, rgmii1, rgmii2,
-                 mdio, nand1, nand2, sdhci]
-
 additionalProperties: false
 
 examples:
@@ -55,14 +54,9 @@ examples:
   - |
     pinctrl {
       compatible = "ralink,rt2880-pinmux";
-      pinctrl-names = "default";
-      pinctrl-0 = <&state_default>;
 
-      state_default: pinctrl0 {
+      i2c_pins: i2c0-pins {
-      };
+        pinmux {
-
-      i2c_pins: i2c0 {
-        i2c0 {
           groups = "i2c";
           function = "i2c";
         };