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

*** 92,102 ****
  /* segkpm support */
  static caddr_t  segmap_pagecreate_kpm(struct seg *, vnode_t *, u_offset_t,
                          struct smap *, enum seg_rw);
  struct smap     *get_smap_kpm(caddr_t, page_t **);
  
! static struct seg_ops segmap_ops = {
          .free           = segmap_free,
          .fault          = segmap_fault,
          .faulta         = segmap_faulta,
          .checkprot      = segmap_checkprot,
          .kluster        = segmap_kluster,
--- 92,102 ----
  /* segkpm support */
  static caddr_t  segmap_pagecreate_kpm(struct seg *, vnode_t *, u_offset_t,
                          struct smap *, enum seg_rw);
  struct smap     *get_smap_kpm(caddr_t, page_t **);
  
! static const struct seg_ops segmap_ops = {
          .free           = segmap_free,
          .fault          = segmap_fault,
          .faulta         = segmap_faulta,
          .checkprot      = segmap_checkprot,
          .kluster        = segmap_kluster,