Bluetooth: Add 'dst_type' field to struct hci_conn

This patch adds a new field (dst_type) to the struct hci_conn which
holds the type of the destination address (bdaddr_t dst). This
approach is needed in order to use the struct hci_conn as an
abstraction of LE connections in HCI Layer. For non-LE this field
is ignored.

This patch also set properly the 'dst_type' field after initializing
LE hci_conn structures.

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>