Bluetooth: Add support for changing the public device address

This adds support for changing the public device address. This feature
is required by controllers that do not provide a public address and
have HCI_QUIRK_INVALID_BDADDR set.

Even if a controller has a public device address, this is useful when
an embedded system wants to use its own value. As long as the driver
provides the set_bdaddr callback, this allows changing the device
address before powering on the controller.

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