6639 uhci_qh walker contains whacky boolean logic

*** 22,33 ****
  /*
   * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  
- #pragma ident   "%Z%%M% %I%     %E% SMI"
- 
  #include <gelf.h>
  
  #include <sys/mdb_modapi.h>
  #include <mdb/mdb_ks.h>
  
--- 22,31 ----
*** 582,593 ****
          if (wsp->walk_addr == NULL || wsp->walk_addr & HC_END_OF_LIST)  {
                  return (WALK_DONE);
          }
  
          /* Make sure next element is a QH.  If a TD, stop.  */
!         if (!  ((((queue_head_t *)wsp->walk_data)->link_ptr) & HC_QUEUE_HEAD)
!             == HC_QUEUE_HEAD)  {
                  return (WALK_DONE);
          }
  
          /* Strip terminate etc. bits.  */
          wsp->walk_addr &= QH_LINK_PTR_MASK;
--- 580,591 ----
          if (wsp->walk_addr == NULL || wsp->walk_addr & HC_END_OF_LIST)  {
                  return (WALK_DONE);
          }
  
          /* Make sure next element is a QH.  If a TD, stop.  */
!         if (((((queue_head_t *)wsp->walk_data)->link_ptr) & HC_QUEUE_HEAD)
!             != HC_QUEUE_HEAD)  {
                  return (WALK_DONE);
          }
  
          /* Strip terminate etc. bits.  */
          wsp->walk_addr &= QH_LINK_PTR_MASK;