Defines starting with `d' in bsd/netat

• DBG_AT_DDP_INPUT bsd/netat/at_kdebug.h:41
• DDPCLONEMIN bsd/netat/ddp_proto.c:57
• DEF_SESS_TMO bsd/netat/asp_proto.c:57
• DIRECT_ADDR bsd/netat/ddp.c:836
• DSAP_SNAP bsd/netat/drv_dep.c:55