2976 remove useless offsetof() macros

*** 21,39 ****
  /*
   * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  
- #pragma ident   "%Z%%M% %I%     %E% SMI"
- 
  #include <meta.h>
  #include <assert.h>
  #include <ctype.h>
  #include <mdiox.h>
  #include <meta.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <strings.h>
  #include <sys/lvm/md_mddb.h>
  #include <sys/lvm/md_names.h>
  #include <sys/lvm/md_crc.h>
  #include <sys/lvm/md_convert.h>
--- 21,38 ----
  /*
   * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  
  #include <meta.h>
  #include <assert.h>
  #include <ctype.h>
  #include <mdiox.h>
  #include <meta.h>
  #include <stdio.h>
  #include <stdlib.h>
+ #include <stddef.h>
  #include <strings.h>
  #include <sys/lvm/md_mddb.h>
  #include <sys/lvm/md_names.h>
  #include <sys/lvm/md_crc.h>
  #include <sys/lvm/md_convert.h>
*** 159,169 ****
   * MAXSIZEMDRECNAME is the value that has historically been used to allocate
   * space for the metadevice name
   */
  #define MAXSIZEMDRECNAME        20
  #define NAMEWIDTH               16
- #define offsetof(s, m)  ((size_t)(&(((s *)0)->m)))
  #define NOT_PHYSICAL_DEV        0
  #define PHYSICAL_DEV            1
  
  
  /*
--- 158,167 ----