dt-bindings: phy: Move the Cadence D-PHY bindings

The Cadence D-PHY bindings was defined as part of the DSI block so far.
However, since it's now going to be a separate driver, we need to move the
binding to a file of its own.

Acked-by: Sakari Ailus <[e-mail]>
Signed-off-by: Maxime Ripard <[e-mail]>
Signed-off-by: Kishon Vijay Abraham I <[e-mail]>

Documentation/devicetree/bindings/display/bridge/cdns,dsi.txt

···
 - one subnode per DSI device connected on the DSI bus. Each DSI device should
   contain a reg property encoding its virtual channel.
 
-Cadence DPHY
-============
-
-Cadence DPHY block.
-
-Required properties:
-- compatible: should be set to "cdns,dphy".
-- reg: physical base address and length of the DPHY registers.
-- clocks: DPHY reference clocks.
-- clock-names: must contain "psm" and "pll_ref".
-- #phy-cells: must be set to 0.
-
-
 Example:
-	dphy0: dphy@fd0e0000{
-		compatible = "cdns,dphy";
-		reg = <0x0 0xfd0e0000 0x0 0x1000>;
-		clocks = <&psm_clk>, <&pll_ref_clk>;
-		clock-names = "psm", "pll_ref";
-		#phy-cells = <0>;
-	};
-
 	dsi0: dsi@fd0c0000 {
 		compatible = "cdns,dsi";
 		reg = <0x0 0xfd0c0000 0x0 0x1000>;

Documentation/devicetree/bindings/phy/cdns,dphy.txt

···
+Cadence DPHY
+============
+
+Cadence DPHY block.
+
+Required properties:
+- compatible: should be set to "cdns,dphy".
+- reg: physical base address and length of the DPHY registers.
+- clocks: DPHY reference clocks.
+- clock-names: must contain "psm" and "pll_ref".
+- #phy-cells: must be set to 0.
+
+Example:
+	dphy0: dphy@fd0e0000{
+		compatible = "cdns,dphy";
+		reg = <0x0 0xfd0e0000 0x0 0x1000>;
+		clocks = <&psm_clk>, <&pll_ref_clk>;
+		clock-names = "psm", "pll_ref";
+		#phy-cells = <0>;
+	};