Bluetooth: Pass desired connection role to hci_connect_le()

If we have both LE scanning and advertising simultaneously enabled we
need a way to tell hci_connect_le() in which role to initiate a
connection. This patch adds a new parameter to the function to give it
the necessary information. For auto-connect and mgmt_pair_device we
always use master role, whereas for L2CAP users (in practice sockets) we
use slave role whenever HCI_ADVERTISING is set and master role
otherwise.

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