dt-bindings: net: bluetooth: nxp: Add wakeup pin properties

NXP bluetooth controller may have GPIO pins used and routed for `WAKE_IN`
and `WAKE_OUT`, such pin info must be known so that the driver is can
configure the controller's firmware accordingly.

Signed-off-by: Loic Poulain <[e-mail]>
Reviewed-by: Rob Herring (Arm) <[e-mail]>
Signed-off-by: Luiz Augusto von Dentz <[e-mail]>

Documentation/devicetree/bindings/net/bluetooth/nxp,88w8987-bt.yaml

···
       Host-To-Chip power save mechanism is driven by this GPIO
       connected to BT_WAKE_IN pin of the NXP chipset.
 
+  nxp,wakein-pin:
+    $ref: /schemas/types.yaml#/definitions/uint8
+    description:
+      The GPIO number of the NXP chipset used for BT_WAKE_IN.
+
+  nxp,wakeout-pin:
+    $ref: /schemas/types.yaml#/definitions/uint8
+    description:
+      The GPIO number of the NXP chipset used for BT_WAKE_OUT.
+
 required:
   - compatible
 
···
             fw-init-baudrate = <3000000>;
             firmware-name = "uartuart8987_bt_v0.bin";
             device-wakeup-gpios = <&gpio 11 GPIO_ACTIVE_HIGH>;
+            nxp,wakein-pin = /bits/ 8 <18>;
+            nxp,wakeout-pin = /bits/ 8 <19>;
         };
     };