Bluetooth: Add address type to struct sockaddr_l2

This patch adds the address type info to struct sockaddr_l2 so
user-space can inform the remote device address type required
to establish LE connections.

Soon, instead of looking the advertising cache up to discover the
address type, we'll use this address type info to establish LE
connections.

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Acked-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>