Bluetooth: Add LE connection support to L2CAP

Add basic LE connection support to L2CAP. LE
connection can be created by specifying cid
in struct sockaddr_l2

Signed-off-by: Ville Tervo <ville.tervo@nokia.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>