dt-bindings: watchdog: move i.MX system controller watchdog binding to SCU

i.MX system controller watchdog depends on SCU driver to support
interrupt function, so it needs to be subnode of SCU node in DT,
binding doc should be moved to fsl,scu.txt as well.
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

Documentation/devicetree/bindings/arm/freescale/fsl,scu.txt

@@ -133,6 +133,16 @@ RTC bindings based on SCU Message Protocol
 Required properties:
 - compatible: should be "fsl,imx8qxp-sc-rtc";
 
+Watchdog bindings based on SCU Message Protocol
+------------------------------------------------------------
+
+Required properties:
+- compatible: should be:
+              "fsl,imx8qxp-sc-wdt"
+              followed by "fsl,imx-sc-wdt";
+Optional properties:
+- timeout-sec: contains the watchdog timeout in seconds.
+
 Example (imx8qxp):
 -------------
 aliases {
@@ -185,6 +195,11 @@ firmware {
 		rtc: rtc {
 			compatible = "fsl,imx8qxp-sc-rtc";
 		};
+
+		watchdog {
+			compatible = "fsl,imx8qxp-sc-wdt", "fsl,imx-sc-wdt";
+			timeout-sec = <60>;
+		};
 	};
 };
 

Documentation/devicetree/bindings/watchdog/fsl-imx-sc-wdt.txt

-* Freescale i.MX System Controller Watchdog
-
-i.MX system controller watchdog is for i.MX SoCs with system controller inside,
-the watchdog is managed by system controller, users can ONLY communicate with
-system controller from secure mode for watchdog operations, so Linux i.MX system
-controller watchdog driver will call ARM SMC API and trap into ARM-Trusted-Firmware
-for watchdog operations, ARM-Trusted-Firmware is running at secure EL3 mode and
-it will request system controller to execute the watchdog operation passed from
-Linux kernel.
-
-Required properties:
-- compatible:	Should be :
-		"fsl,imx8qxp-sc-wdt"
-		followed by "fsl,imx-sc-wdt";
-
-Optional properties:
-- timeout-sec : Contains the watchdog timeout in seconds.
-
-Examples:
-
-watchdog {
-	compatible = "fsl,imx8qxp-sc-wdt", "fsl,imx-sc-wdt";
-	timeout-sec = <60>;
-};