spi/ppc4xx: Use kcalloc() in spi_ppc4xx_of_probe()

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

  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: Mark Brown <broonie@kernel.org>

drivers/spi/spi-ppc4xx.c

@@ -411,7 +411,7 @@ static int spi_ppc4xx_of_probe(struct platform_device *op)
 	if (num_gpios > 0) {
 		int i;
 
-		hw->gpios = kzalloc(sizeof(int) * num_gpios, GFP_KERNEL);
+		hw->gpios = kcalloc(num_gpios, sizeof(*hw->gpios), GFP_KERNEL);
 		if (!hw->gpios) {
 			ret = -ENOMEM;
 			goto free_master;