Bluetooth: Use seperate socket for LE ATT Server

Because traffic between the local GATT client(s) and
remote servers are subject to different controls than
remote clients and the local server, all on the shared
fixed CID, it is important to manage the traffic on
seperate sockets.

Change-Id: I62385143c86522f4b123b32592b69f2a0ae6dc76
CRs-fixed: 336029
Signed-off-by: Brian Gix <bgix@codeaurora.org>