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

*** 203,214 ****
  #define P_HASHWIRED_MASK                (seg_phashsize_wired - 1)
  #define P_BASESHIFT                     (6)
  
  kthread_t *seg_pasync_thr;
  
! extern struct seg_ops segvn_ops;
! extern struct seg_ops segspt_shmops;
  
  #define IS_PFLAGS_WIRED(flags) ((flags) & SEGP_FORCE_WIRED)
  #define IS_PCP_WIRED(pcp) IS_PFLAGS_WIRED((pcp)->p_flags)
  
  #define LBOLT_DELTA(t)  ((ulong_t)(ddi_get_lbolt() - (t)))
--- 203,214 ----
  #define P_HASHWIRED_MASK                (seg_phashsize_wired - 1)
  #define P_BASESHIFT                     (6)
  
  kthread_t *seg_pasync_thr;
  
! extern const struct seg_ops segvn_ops;
! extern const struct seg_ops segspt_shmops;
  
  #define IS_PFLAGS_WIRED(flags) ((flags) & SEGP_FORCE_WIRED)
  #define IS_PCP_WIRED(pcp) IS_PFLAGS_WIRED((pcp)->p_flags)
  
  #define LBOLT_DELTA(t)  ((ulong_t)(ddi_get_lbolt() - (t)))