dt-bindings: clock: silabs,si5341: Add missing properties

Add "clock-output-names" which is a standard property for clock
providers.

Add the "always-on" boolean property which was undocumented, but
already in use for some time. The flag prevents a clock output from
being disabled.

Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
Tested-by: Michal Simek <michal.simek@amd.com>
Reviewed-by: Michal Simek <michal.simek@amd.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

Author: robherring

Documentation/devicetree/bindings/clock/silabs,si5341.yaml

@@ -73,6 +73,8 @@ properties:
       - const: in1
       - const: in2
 
+  clock-output-names: true
+
   interrupts:
     maxItems: 1
     description: Interrupt for INTRb pin
@@ -130,6 +132,10 @@ patternProperties:
         description: Number of clock output
         maximum: 9
 
+      always-on:
+        description: Set to keep the clock output always running
+        type: boolean
+
       silabs,format:
         description: Output format
         $ref: /schemas/types.yaml#/definitions/uint32