Bluetooth: Don't send store hint for devices using identity addresses

The identity resolving keys should only be stored for devices using
resolvable random addresses. If the device is already using an
identity address, inform it about the new identity resolving key,
but tell userspace that this key is not persistent.

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