dt-bindings: clk: rs9: Fix DIF pattern match

The pattern match [0-19] is incorrect and does not cover range of 0..19,
use pattern 1?[0-9] to cover range 0..19 instead. Update the example to
validate all parts of the pattern match and prevent such failures in the
future.

Fixes: 26c1bc6 ("dt-bindings: clk: rs9: Add Renesas 9-series I2C PCIe clock generator")
Signed-off-by: Marek Vasut <marek.vasut@mailbox.org>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

Author: Marek Vasut

Documentation/devicetree/bindings/clock/renesas,9series.yaml

@@ -62,7 +62,7 @@ properties:
     description: Output clock down spread in pcm (1/1000 of percent)
 
 patternProperties:
-  "^DIF[0-19]$":
+  "^DIF1?[0-9]$":
     type: object
     description:
       Description of one of the outputs (DIF0..DIF19).
@@ -107,6 +107,15 @@ examples:
             DIF0 {
                 renesas,slew-rate = <3000000>;
             };
+
+            /* Not present on 9FGV0241, used for DT validation only */
+            DIF2 {
+                renesas,slew-rate = <2000000>;
+            };
+
+            DIF19 {
+                renesas,slew-rate = <3000000>;
+            };
         };
     };