5045 use atomic_{inc,dec}_* instead of atomic_add_*

*** 315,325 ****
      uint_t nhashwon;
      uint_t nnotfound;
  } memseg_stats;
  
  #define MEMSEG_STAT_INCR(v) \
!         atomic_add_32(&memseg_stats.v, 1)
  #else
  #define MEMSEG_STAT_INCR(x)
  #endif
  
  struct memseg *memsegs;         /* list of memory segments */
--- 315,325 ----
      uint_t nhashwon;
      uint_t nnotfound;
  } memseg_stats;
  
  #define MEMSEG_STAT_INCR(v) \
!         atomic_inc_32(&memseg_stats.v)
  #else
  #define MEMSEG_STAT_INCR(x)
  #endif
  
  struct memseg *memsegs;         /* list of memory segments */