Bluetooth: Store the source address type of LE connections

When establishing LE connections, it is possible to use a public
address (if available) or a random address. The type of address
is only known when creating connections, so make sure it is
stored in hci_conn structure.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>