5042 stop using deprecated atomic functions

*** 72,82 ****
  #define KEYSOCK_MAX_CONSUMERS 256
          struct keysock_consumer_s *keystack_consumers[KEYSOCK_MAX_CONSUMERS];
  
          /*
           * State for flush/dump.  This would normally be a boolean_t, but
!          * cas32() works best for a known 32-bit quantity.
           */
          uint32_t                keystack_flushdump;
          int                     keystack_flushdump_errno;
  
          /*
--- 72,82 ----
  #define KEYSOCK_MAX_CONSUMERS 256
          struct keysock_consumer_s *keystack_consumers[KEYSOCK_MAX_CONSUMERS];
  
          /*
           * State for flush/dump.  This would normally be a boolean_t, but
!          * atomic_cas_32() works best for a known 32-bit quantity.
           */
          uint32_t                keystack_flushdump;
          int                     keystack_flushdump_errno;
  
          /*