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>
diff --git a/include/net/bluetooth/a2mp.h b/include/net/bluetooth/a2mp.h
index e776ab2..42f2176 100644
--- a/include/net/bluetooth/a2mp.h
+++ b/include/net/bluetooth/a2mp.h
@@ -133,7 +133,7 @@
 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,