6154 const-ify segment ops structures

*** 228,238 ****
  } svntr_stats_t;
  
  extern void     segvn_init(void);
  extern int      segvn_create(struct seg *, void *);
  
! extern  struct seg_ops segvn_ops;
  
  /*
   * Provided as shorthand for creating user zfod segments.
   */
  extern  caddr_t zfod_argsp;
--- 228,238 ----
  } svntr_stats_t;
  
  extern void     segvn_init(void);
  extern int      segvn_create(struct seg *, void *);
  
! extern const struct seg_ops segvn_ops;
  
  /*
   * Provided as shorthand for creating user zfod segments.
   */
  extern  caddr_t zfod_argsp;