Bluetooth: Fix advertising data flags with disabled BR/EDR

We shouldn't include the simultaneous LE & BR/EDR flags in the LE
advertising data if BR/EDR is disabled on a dual-mode controller. This
patch fixes this issue and ensures that the create_ad function generates
the correct flags when BR/EDR is disabled.

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