Bluetooth: Limit fast connectable support to >= 1.2 controllers

The HCI commands that are necessary for fast connectable mode are only
available from HCI specification version 1.2 onwards. This should be
reflected in the supported settings as well as error response for the
set_fast_connectable command when dealing with a < 1.2 capable
controller.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>