reset: sti: Use devm_kcalloc() in syscfg_reset_controller_register()

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

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

* Delete the local variable "size" which became unnecessary with
  this refactoring.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

drivers/reset/sti/reset-syscfg.c

@@ -145,16 +145,14 @@ static int syscfg_reset_controller_register(struct device *dev,
 				const struct syscfg_reset_controller_data *data)
 {
 	struct syscfg_reset_controller *rc;
-	size_t size;
 	int i, err;
 
 	rc = devm_kzalloc(dev, sizeof(*rc), GFP_KERNEL);
 	if (!rc)
 		return -ENOMEM;
 
-	size = sizeof(struct syscfg_reset_channel) * data->nr_channels;
-
-	rc->channels = devm_kzalloc(dev, size, GFP_KERNEL);
+	rc->channels = devm_kcalloc(dev, data->nr_channels,
+				    sizeof(*rc->channels), GFP_KERNEL);
 	if (!rc->channels)
 		return -ENOMEM;