amdkfd: use calloc instead of kzalloc to avoid integer overflow

This uses calloc instead of doing the multiplication which might
overflow.

Cc: stable@vger.kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/amd/amdkfd/kfd_chardev.c

@@ -779,8 +779,8 @@ static int kfd_ioctl_get_process_apertures_new(struct file *filp,
 	 * nodes, but not more than args->num_of_nodes as that is
 	 * the amount of memory allocated by user
 	 */
-	pa = kzalloc((sizeof(struct kfd_process_device_apertures) *
-				args->num_of_nodes), GFP_KERNEL);
+	pa = kcalloc(args->num_of_nodes, sizeof(struct kfd_process_device_apertures),
+		     GFP_KERNEL);
 	if (!pa)
 		return -ENOMEM;