5045 use atomic_{inc,dec}_* instead of atomic_add_*

*** 936,946 ****
           * that was running when the interrupt went off.
           */
          if (t->t_flag & T_INTR_THREAD) {
                  klwp_t *lwp;
  
!                 atomic_add_32(&kcpc_intrctx_count, 1);
  
                  /*
                   * Note that t_lwp is always set to point at the underlying
                   * thread, thus this will work in the presence of nested
                   * interrupts.
--- 936,946 ----
           * that was running when the interrupt went off.
           */
          if (t->t_flag & T_INTR_THREAD) {
                  klwp_t *lwp;
  
!                 atomic_inc_32(&kcpc_intrctx_count);
  
                  /*
                   * Note that t_lwp is always set to point at the underlying
                   * thread, thus this will work in the presence of nested
                   * interrupts.
*** 1006,1016 ****
                          panic("null cpc context, thread %p", (void *)t);
  #ifdef DEBUG
                  cmn_err(CE_NOTE,
                      "null cpc context found in overflow handler!\n");
  #endif
!                 atomic_add_32(&kcpc_nullctx_count, 1);
          } else if ((ctx->kc_flags & KCPC_CTX_INVALID) == 0) {
                  /*
                   * Schedule an ast to sample the counters, which will
                   * propagate any overflow into the virtualized performance
                   * counter(s), and may deliver a signal.
--- 1006,1016 ----
                          panic("null cpc context, thread %p", (void *)t);
  #ifdef DEBUG
                  cmn_err(CE_NOTE,
                      "null cpc context found in overflow handler!\n");
  #endif
!                 atomic_inc_32(&kcpc_nullctx_count);
          } else if ((ctx->kc_flags & KCPC_CTX_INVALID) == 0) {
                  /*
                   * Schedule an ast to sample the counters, which will
                   * propagate any overflow into the virtualized performance
                   * counter(s), and may deliver a signal.