Bluetooth: Add a role parameter to hci_conn_add()

We need to be able to track slave vs master LE connections in
hci_conn_hash, and to be able to do that we need to know the role of the
connection by the time hci_conn_add_has() is called. This means in
practice the hci_conn_add() call that creates the hci_conn_object.

This patch adds a new role parameter to hci_conn_add() function to give
the object its initial role value, and updates the callers to pass the
appropriate role to it. Since the function now takes care of
initializing both conn->role and conn->out values we can remove some
other unnecessary assignments.

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