Bluetooth: L2CAP: Introduce security requirements on CoC

Applies on L2CAP channel object security requirement member and
implements on BR/EDR transport basic security cases during incoming
CoC connection request. Since channel security requirements can involve
sending 2 separate connection responses with proper results depending on
context path, there's a need to store L2CAP signaling identifier set in
original connection request to be restored later to help match proper
response context.

Change-Id: Ibac9a5d2443f2975637e1bd15f61afcad53f843b
Signed-off-by: Arkadiusz Lichwa <arkadiusz.lichwa@tieto.com>