ioat1: trim ioat_dma_desc_sw

Save 4 bytes per software descriptor by transmitting tx_cnt in an unused
portion of the hardware descriptor.

Signed-off-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/drivers/dma/ioat/dma.c b/drivers/dma/ioat/dma.c
index abc96c4..f59b6f4 100644
--- a/drivers/dma/ioat/dma.c
+++ b/drivers/dma/ioat/dma.c
@@ -396,7 +396,7 @@
 	dump_desc_dbg(ioat, chain_tail);
 	dump_desc_dbg(ioat, first);
 
-	ioat->pending += desc->tx_cnt;
+	ioat->pending += desc->hw->tx_cnt;
 	if (ioat->pending >= ioat_pending_level)
 		__ioat1_dma_memcpy_issue_pending(ioat);
 	spin_unlock_bh(&ioat->desc_lock);
@@ -655,11 +655,11 @@
 	spin_unlock_bh(&ioat->desc_lock);
 
 	desc->txd.flags = flags;
-	desc->tx_cnt = tx_cnt;
 	desc->len = total_len;
 	list_splice(&chain, &desc->txd.tx_list);
 	hw->ctl_f.int_en = !!(flags & DMA_PREP_INTERRUPT);
 	hw->ctl_f.compl_write = 1;
+	hw->tx_cnt = tx_cnt;
 	dump_desc_dbg(ioat, desc);
 
 	return &desc->txd;