2976 remove useless offsetof() macros

*** 54,63 ****
--- 54,64 ----
  #include <sys/sunddi.h>
  #include <sys/sunldi.h>
  #include <sys/pmem.h>
  #include <sys/agpgart.h>
  #include <sys/time.h>
+ #include <sys/sysmacros.h>
  #include "drm_atomic.h"
  #include "drm.h"
  #include "queue.h"
  #include "drm_linux_list.h"