ATM-ZeitNet: Use kmalloc_array() in start_tx()

* A multiplication for the size determination of a memory allocation
  indicated that an array data structure should be processed.
  Thus use the corresponding function "kmalloc_array".

  This issue was detected by using the Coccinelle software.

* Replace the specification of a data type by a pointer dereference
  to make the corresponding size determination a bit safer according to
  the Linux coding style convention.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/atm/zatm.c

@@ -998,8 +998,9 @@ static int start_tx(struct atm_dev *dev)
 
 	DPRINTK("start_tx\n");
 	zatm_dev = ZATM_DEV(dev);
-	zatm_dev->tx_map = kmalloc(sizeof(struct atm_vcc *)*
-	    zatm_dev->chans,GFP_KERNEL);
+	zatm_dev->tx_map = kmalloc_array(zatm_dev->chans,
+					 sizeof(*zatm_dev->tx_map),
+					 GFP_KERNEL);
 	if (!zatm_dev->tx_map) return -ENOMEM;
 	zatm_dev->tx_bw = ATM_OC3_PCR;
 	zatm_dev->free_shapers = (1 << NR_SHAPERS)-1;