Bluetooth: Use zalloc when possible

Use zallog for adv_instance allocation instead of kmalloc + memset.
This also fixes the following coccinelle warning:

>> net/bluetooth/hci_core.c:2693:17-24: WARNING: kzalloc should be
used for adv_instance, instead of kmalloc/memset
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

net/bluetooth/hci_core.c

@@ -2716,11 +2716,10 @@ int hci_add_adv_instance(struct hci_dev *hdev, u8 instance, u32 flags,
 		    instance < 1 || instance > HCI_MAX_ADV_INSTANCES)
 			return -EOVERFLOW;
 
-		adv_instance = kmalloc(sizeof(*adv_instance), GFP_KERNEL);
+		adv_instance = kzalloc(sizeof(*adv_instance), GFP_KERNEL);
 		if (!adv_instance)
 			return -ENOMEM;
 
-		memset(adv_instance, 0, sizeof(*adv_instance));
 		adv_instance->pending = true;
 		adv_instance->instance = instance;
 		list_add(&adv_instance->list, &hdev->adv_instances);