2976 remove useless offsetof() macros

*** 72,81 ****
--- 72,82 ----
  #include <sys/dkio.h>
  #include <sys/vtoc.h>
  #include <sys/cmn_err.h>
  #include <sys/modctl.h>
  #include <sys/ddi.h>
+ #include <sys/sysmacros.h>
  #include <sys/sunddi.h>
  #include <sys/sunldi.h>
  #include <sys/nsctl/nsvers.h>
  
  #include <sys/nsc_thread.h>
*** 2413,2427 ****
          }
  
          return (0);
  }
  
- 
- #ifndef offsetof
- #define offsetof(s, m)  ((size_t)(&((s *)0)->m))
- #endif
- 
  /*
   * re-write the size of the current partition
   */
  static int
  sv_fix_dkiocgvtoc(const intptr_t arg, const int mode, sv_dev_t *svp)
--- 2414,2423 ----