dt-bindings: clock: versaclock3: Add description for #clock-cells property

Add description for "#clock-cells" property to map indexes to the clock
output in the Table 3. ("Output Source") in the 5P35023 datasheet
(ie: {REF,SE1,SE2,SE3,DIFF1,DIFF2}. Also update the "assigned-clock-rates"
in the example.

While at it, replace clocks phandle in the example from x1_x2->x1 as
X2 is a different 32768 kHz crystal.
Suggested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230824104812.147775-2-biju.das.jz@bp.renesas.comReviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

Documentation/devicetree/bindings/clock/renesas,5p35023.yaml

@@ -37,6 +37,9 @@ properties:
     maxItems: 1
 
   '#clock-cells':
+    description:
+      The index in the assigned-clocks is mapped to the output clock as below
+      0 - REF, 1 - SE1, 2 - SE2, 3 - SE3, 4 - DIFF1, 5 - DIFF2.
     const: 1
 
   clocks:
@@ -68,7 +71,7 @@ examples:
             reg = <0x68>;
             #clock-cells = <1>;
 
-            clocks = <&x1_x2>;
+            clocks = <&x1>;
 
             renesas,settings = [
                 80 00 11 19 4c 02 23 7f 83 19 08 a9 5f 25 24 bf
@@ -79,8 +82,8 @@ examples:
             assigned-clocks = <&versa3 0>, <&versa3 1>,
                               <&versa3 2>, <&versa3 3>,
                               <&versa3 4>, <&versa3 5>;
-            assigned-clock-rates = <12288000>, <25000000>,
-                                   <12000000>, <11289600>,
-                                   <11289600>, <24000000>;
+            assigned-clock-rates = <24000000>, <11289600>,
+                                   <11289600>, <12000000>,
+                                   <25000000>, <12288000>;
         };
     };