Bluetooth: Do not call rfcomm_session_put() for RFCOMM UA on closed socket
When processing a RFCOMM UA frame when the socket is closed and we were
not the RFCOMM initiator would cause rfcomm_session_put() to be called
twice during rfcomm_process_rx(). This would cause a kernel panic in
rfcomm_session_close() then.
This could be easily reproduced during disconnect with devices such as
Motorola H270 that send RFCOMM UA followed quickly by L2CAP disconnect
request. This trace for this looks like: