7819 IPv6 Packet and MTU bug

*** 20,29 ****
--- 20,30 ----
   */
  
  /*
   * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
+  * Copyright 2017 OmniTI Computer Consulting, Inc. All rights reserved.
   */
  /* Copyright (c) 1990 Mentat Inc. */
  
  #include <sys/types.h>
  #include <sys/stream.h>
*** 243,253 ****
                      ipst->ips_ip_pathmtu_interval) {
                          /*
                           * Older than 20 minutes. Drop the path MTU information.
                           */
                          mutex_enter(&dce->dce_lock);
!                         dce->dce_flags &= ~(DCEF_PMTU|DCEF_TOO_SMALL_PMTU);
                          dce->dce_last_change_time = TICK_TO_SEC(now);
                          mutex_exit(&dce->dce_lock);
                          dce_increment_generation(dce);
                          ixa->ixa_fragsize = ip_get_base_mtu(nce->nce_ill, ire);
                  } else {
--- 244,254 ----
                      ipst->ips_ip_pathmtu_interval) {
                          /*
                           * Older than 20 minutes. Drop the path MTU information.
                           */
                          mutex_enter(&dce->dce_lock);
!                         dce->dce_flags &= ~DCEF_PMTU;
                          dce->dce_last_change_time = TICK_TO_SEC(now);
                          mutex_exit(&dce->dce_lock);
                          dce_increment_generation(dce);
                          ixa->ixa_fragsize = ip_get_base_mtu(nce->nce_ill, ire);
                  } else {