Bluetooth: AMP: Get amp_mgr reference in HS hci_conn

When assigning amp_mgr in hci_conn (type AMP_LINK) get also reference.
In hci_conn_del those references would be put for both conn types
AMP_LINK and ACL_LINK associated with amp_mgr.
Signed-off-by: Andrei Emeltchenko <andrei.emeltchenko@intel.com>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>

include/net/bluetooth/a2mp.h

@@ -133,7 +133,7 @@ struct a2mp_physlink_rsp {
 extern struct list_head amp_mgr_list;
 extern struct mutex amp_mgr_list_lock;
 
-void amp_mgr_get(struct amp_mgr *mgr);
+struct amp_mgr *amp_mgr_get(struct amp_mgr *mgr);
 int amp_mgr_put(struct amp_mgr *mgr);
 u8 __next_ident(struct amp_mgr *mgr);
 struct l2cap_chan *a2mp_channel_create(struct l2cap_conn *conn,

net/bluetooth/a2mp.c

@@ -751,11 +751,13 @@ static struct l2cap_chan *a2mp_chan_open(struct l2cap_conn *conn, bool locked)
 }
 
 /* AMP Manager functions */
-void amp_mgr_get(struct amp_mgr *mgr)
+struct amp_mgr *amp_mgr_get(struct amp_mgr *mgr)
 {
 	BT_DBG("mgr %p orig refcnt %d", mgr, atomic_read(&mgr->kref.refcount));
 
 	kref_get(&mgr->kref);
+
+	return mgr;
 }
 
 static void amp_mgr_destroy(struct kref *kref)

net/bluetooth/amp.c

@@ -123,7 +123,7 @@ struct hci_conn *phylink_add(struct hci_dev *hdev, struct amp_mgr *mgr,
 	hcon->attempt++;
 	hcon->handle = __next_handle(mgr);
 	hcon->remote_id = remote_id;
-	hcon->amp_mgr = mgr;
+	hcon->amp_mgr = amp_mgr_get(mgr);
 	hcon->out = out;
 
 	return hcon;