dt-bindings: phy: bcm-ns-usb3-phy: convert to yaml

1. Change syntax from txt to yaml
2. Drop "Driver for" from the title
3. Drop "reg = <0x0>;" from example (noticed by dt_binding_check)
4. Specify license
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210329165056.31647-1-zajec5@gmail.comSigned-off-by: Vinod Koul <vkoul@kernel.org>

Documentation/devicetree/bindings/phy/bcm-ns-usb3-phy.txt

-Driver for Broadcom Northstar USB 3.0 PHY
-
-Required properties:
-
-- compatible: one of: "brcm,ns-ax-usb3-phy", "brcm,ns-bx-usb3-phy".
-- reg: address of MDIO bus device
-- usb3-dmp-syscon: phandle to syscon with DMP (Device Management Plugin)
-		   registers
-- #phy-cells: must be 0
-
-Initialization of USB 3.0 PHY depends on Northstar version. There are currently
-three known series: Ax, Bx and Cx.
-Known A0: BCM4707 rev 0
-Known B0: BCM4707 rev 4, BCM53573 rev 2
-Known B1: BCM4707 rev 6
-Known C0: BCM47094 rev 0
-
-Example:
-	mdio: mdio@0 {
-		reg = <0x0>;
-		#size-cells = <1>;
-		#address-cells = <0>;
-
-		usb3-phy@10 {
-			compatible = "brcm,ns-ax-usb3-phy";
-			reg = <0x10>;
-			usb3-dmp-syscon = <&usb3_dmp>;
-			#phy-cells = <0>;
-		};
-	};
-
-	usb3_dmp: syscon@18105000 {
-		reg = <0x18105000 0x1000>;
-	};

Documentation/devicetree/bindings/phy/bcm-ns-usb3-phy.yaml

+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/phy/bcm-ns-usb3-phy.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Broadcom Northstar USB 3.0 PHY
+
+description: |
+  Initialization of USB 3.0 PHY depends on Northstar version. There are currently
+  three known series: Ax, Bx and Cx.
+  Known A0: BCM4707 rev 0
+  Known B0: BCM4707 rev 4, BCM53573 rev 2
+  Known B1: BCM4707 rev 6
+  Known C0: BCM47094 rev 0
+
+maintainers:
+  - Rafał Miłecki <rafal@milecki.pl>
+
+properties:
+  compatible:
+    enum:
+      - brcm,ns-ax-usb3-phy
+      - brcm,ns-bx-usb3-phy
+
+  reg:
+    description: address of MDIO bus device
+    maxItems: 1
+
+  usb3-dmp-syscon:
+    $ref: /schemas/types.yaml#/definitions/phandle
+    description:
+      Phandle to the DMP (Device Management Plugin) syscon
+
+  "#phy-cells":
+    const: 0
+
+required:
+  - compatible
+  - reg
+  - usb3-dmp-syscon
+  - "#phy-cells"
+
+additionalProperties: false
+
+examples:
+  - |
+    mdio {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        usb3-phy@10 {
+            compatible = "brcm,ns-ax-usb3-phy";
+            reg = <0x10>;
+            usb3-dmp-syscon = <&usb3_dmp>;
+            #phy-cells = <0>;
+        };
+    };
+
+    usb3_dmp: syscon@18105000 {
+        reg = <0x18105000 0x1000>;
+    };