Adjust a comment

hdl/rtl/hydra_supervisor_regs.cheby

@@ -49,10 +49,9 @@ memory-map:
         read-strobe: True
   - reg:
       name: wd_period
-      description: Nbr of cycles before watchdog timeout. Can be written once per reset
+      description: Nbr of cycles before watchdog timeout.
       width: 32
       access: rw
-      preset: 2000
       x-hdl:
         write-strobe: True
         type: wire