dt-bindings: clock: amlogic, gxbb-aoclkc: Update bindings

On the first revision of the bindings, only the gates + resets were known
in the AO Clock HW, but more registers used to configures AO clock are known
to be spread among the AO register space.
This patch adds a parent node for the entire system control zone for the AO
domain then moves the clock controller as a subnode of the system control
node.

Signed-off-by: Neil Armstrong <[e-mail]>

Documentation/devicetree/bindings/clock/amlogic,gxbb-aoclkc.txt

···
 
 Required Properties:
 
-- compatible: should be "amlogic,gxbb-aoclkc"
-- reg: physical base address of the clock controller and length of memory
-       mapped region.
+- compatible: value should be different for each SoC family as :
+	- GXBB (S905) : "amlogic,meson-gxbb-aoclkc"
+	- GXL (S905X, S905D) : "amlogic,meson-gxl-aoclkc"
+	- GXM (S912) : "amlogic,meson-gxm-aoclkc"
+	followed by the common "amlogic,meson-gx-aoclkc"
 
 - #clock-cells: should be 1.
 
···
 preprocessor macros in the dt-bindings/reset/gxbb-aoclkc.h header and can be
 used in device tree sources.
 
+Parent node should have the following properties :
+- compatible: "amlogic,meson-gx-ao-sysctrl", "syscon", "simple-mfd"
+- reg: base address and size of the AO system control register space.
+
 Example: AO Clock controller node:
 
-	clkc_AO: clock-controller@040 {
-		compatible = "amlogic,gxbb-aoclkc";
-		reg = <0x0 0x040 0x0 0x4>;
+ao_sysctrl: sys-ctrl@0 {
+	compatible = "amlogic,meson-gx-ao-sysctrl", "syscon", "simple-mfd";
+	reg =  <0x0 0x0 0x0 0x100>;
+
+	clkc_AO: clock-controller {
+		compatible = "amlogic,meson-gxbb-aoclkc", "amlogic,meson-gx-aoclkc";
 		#clock-cells = <1>;
 		#reset-cells = <1>;
 	};
+};
 
 Example: UART controller node that consumes the clock and reset generated
   by the clock controller: