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/net/bluetooth/amp.c b/net/bluetooth/amp.c
index 59da0f1..231d7ef 100644
--- a/net/bluetooth/amp.c
+++ b/net/bluetooth/amp.c
@@ -123,7 +123,7 @@
 	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;