const-ify make segment ops structures
There is no reason to keep the segment ops structures writable.

*** 133,143 ****
  static int      segvn_getmemid(struct seg *seg, caddr_t addr,
                      memid_t *memidp);
  static lgrp_mem_policy_info_t   *segvn_getpolicy(struct seg *, caddr_t);
  static int      segvn_inherit(struct seg *, caddr_t, size_t, uint_t);
  
! struct  seg_ops segvn_ops = {
          .dup            = segvn_dup,
          .unmap          = segvn_unmap,
          .free           = segvn_free,
          .fault          = segvn_fault,
          .faulta         = segvn_faulta,
--- 133,143 ----
  static int      segvn_getmemid(struct seg *seg, caddr_t addr,
                      memid_t *memidp);
  static lgrp_mem_policy_info_t   *segvn_getpolicy(struct seg *, caddr_t);
  static int      segvn_inherit(struct seg *, caddr_t, size_t, uint_t);
  
! const struct seg_ops segvn_ops = {
          .dup            = segvn_dup,
          .unmap          = segvn_unmap,
          .free           = segvn_free,
          .fault          = segvn_fault,
          .faulta         = segvn_faulta,