thunderbolt: Use kcalloc

The advantage of kcalloc is, that will prevent integer overflows
which could result from the multiplication of number of elements
and size and it is also a bit nicer to read.

Signed-off-by: Himangi Saraogi <[e-mail]>
Acked-by: Julia Lawall <[e-mail]>
Acked-by: Andreas Noever <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/thunderbolt/nhi.c

···
 			 nhi->hop_count);
 	INIT_WORK(&nhi->interrupt_work, nhi_interrupt_work);
 
-	nhi->tx_rings = devm_kzalloc(&pdev->dev,
-				     nhi->hop_count * sizeof(*nhi->tx_rings),
-				     GFP_KERNEL);
-	nhi->rx_rings = devm_kzalloc(&pdev->dev,
-				     nhi->hop_count * sizeof(*nhi->rx_rings),
-				     GFP_KERNEL);
+	nhi->tx_rings = devm_kcalloc(&pdev->dev, nhi->hop_count,
+				     sizeof(*nhi->tx_rings), GFP_KERNEL);
+	nhi->rx_rings = devm_kcalloc(&pdev->dev, nhi->hop_count,
+				     sizeof(*nhi->rx_rings), GFP_KERNEL);
 	if (!nhi->tx_rings || !nhi->rx_rings)
 		return -ENOMEM;