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

*** 1298,1308 ****
          txp->xt_mfn = xnb_btop(dma_cookie.dmac_laddress);
          txp->xt_buflen = dma_cookie.dmac_size;
  
          DTRACE_PROBE(txbuf_allocated);
  
!         atomic_add_32(&xnbp->xnb_tx_buf_count, 1);
          xnbp->xnb_tx_buf_outstanding++;
  
          return (0);
  
  failure_2:
--- 1298,1308 ----
          txp->xt_mfn = xnb_btop(dma_cookie.dmac_laddress);
          txp->xt_buflen = dma_cookie.dmac_size;
  
          DTRACE_PROBE(txbuf_allocated);
  
!         atomic_inc_32(&xnbp->xnb_tx_buf_count);
          xnbp->xnb_tx_buf_outstanding++;
  
          return (0);
  
  failure_2:
*** 1324,1334 ****
  
          (void) ddi_dma_unbind_handle(txp->xt_dma_handle);
          ddi_dma_mem_free(&txp->xt_acc_handle);
          ddi_dma_free_handle(&txp->xt_dma_handle);
  
!         atomic_add_32(&xnbp->xnb_tx_buf_count, -1);
  }
  
  /*
   * Take packets from the peer and deliver them onward.
   */
--- 1324,1334 ----
  
          (void) ddi_dma_unbind_handle(txp->xt_dma_handle);
          ddi_dma_mem_free(&txp->xt_acc_handle);
          ddi_dma_free_handle(&txp->xt_dma_handle);
  
!         atomic_dec_32(&xnbp->xnb_tx_buf_count);
  }
  
  /*
   * Take packets from the peer and deliver them onward.
   */