2976 remove useless offsetof() macros

*** 54,66 ****
  #define SF_DEBUG(level, args)
  #endif
  
  static int sf_bus_config_debug = 0;
  
- /* Why do I have to do this? */
- #define offsetof(s, m)  (size_t)(&(((s *)0)->m))
- 
  #include <sys/scsi/scsi.h>
  #include <sys/fc4/fcal.h>
  #include <sys/fc4/fcp.h>
  #include <sys/fc4/fcal_linkapp.h>
  #include <sys/socal_cq_defs.h>
--- 54,63 ----
*** 75,84 ****
--- 72,82 ----
  #include <sys/proc.h>
  #include <sys/kstat.h>
  #include <sys/devctl.h>
  #include <sys/scsi/targets/ses.h>
  #include <sys/callb.h>
+ #include <sys/sysmacros.h>
  
  static int sf_info(dev_info_t *, ddi_info_cmd_t, void *, void **);
  static int sf_attach(dev_info_t *, ddi_attach_cmd_t);
  static int sf_detach(dev_info_t *, ddi_detach_cmd_t);
  static void sf_softstate_unlink(struct sf *);