pch_uart: drop double zeroing

sg_init_table zeroes its first argument, so the allocation of that argument
doesn't have to.

the semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
expression x,n,flags;
@@

x =
- kcalloc
+ kmalloc_array
  (n,sizeof(struct scatterlist),flags)
...
sg_init_table(x,n)
// </smpl>
Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>

Link: https://lore.kernel.org/r/1600601186-7420-2-git-send-email-Julia.Lawall@inria.frSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/pch_uart.c

@@ -981,7 +981,7 @@ static unsigned int dma_handle_tx(struct eg20t_port *priv)
 
 	priv->tx_dma_use = 1;
 
-	priv->sg_tx_p = kcalloc(num, sizeof(struct scatterlist), GFP_ATOMIC);
+	priv->sg_tx_p = kmalloc_array(num, sizeof(struct scatterlist), GFP_ATOMIC);
 	if (!priv->sg_tx_p) {
 		dev_err(priv->port.dev, "%s:kzalloc Failed\n", __func__);
 		return 0;