dt-bindings: net: dp83822: add constraints for mac-termination-ohms

Property mac-termination-ohms is defined in ethernet-phy.yaml. Add allowed
values for the property.

Signed-off-by: Dimitri Fedrau <[e-mail]>
Reviewed-by: Andrew Lunn <[e-mail]>
Reviewed-by: Rob Herring (Arm) <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

Documentation/devicetree/bindings/net/ti,dp83822.yaml

···
       - free-running
       - recovered
 
+  mac-termination-ohms:
+    enum: [43, 44, 46, 48, 50, 53, 55, 58, 61, 65, 69, 73, 78, 84, 91, 99]
+
 required:
   - reg
 
···
         rx-internal-delay-ps = <1>;
         tx-internal-delay-ps = <1>;
         ti,gpio2-clk-out = "xi";
+        mac-termination-ohms = <43>;
       };
     };