dt-bindings: net: dsa: mediatek,mt7530: expand gpio-controller description

Expand the description of the gpio-controller property to include the
controllable pins of the MT7530 switch.

The gpio-controller property is only used for the MT7530 switch. Therefore,
invalidate it for the MT7531 switch.
Signed-off-by: Arınç ÜNAL <arinc.unal@arinc9.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/devicetree/bindings/net/dsa/mediatek,mt7530.yaml

@@ -104,7 +104,14 @@ properties:
   gpio-controller:
     type: boolean
     description:
-      If defined, MT7530's LED controller will run on GPIO mode.
+      If defined, LED controller of the MT7530 switch will run on GPIO mode.
+
+      There are 15 controllable pins.
+      port 0 LED 0..2 as GPIO 0..2
+      port 1 LED 0..2 as GPIO 3..5
+      port 2 LED 0..2 as GPIO 6..8
+      port 3 LED 0..2 as GPIO 9..11
+      port 4 LED 0..2 as GPIO 12..14
 
   "#interrupt-cells":
     const: 1
@@ -263,6 +270,7 @@ allOf:
     then:
       $ref: "#/$defs/mt7531-dsa-port"
       properties:
+        gpio-controller: false
         mediatek,mcm: false
 
   - if: