Bluetooth: btintel: Add MODULE_FIRMWARE entries for iBT 3.5 controllers

The iBT 3.5 controllers (Intel 8265, Windstorm Peak) need
intel/ibt-12-16.sfi and intel/ibt-12-16.ddc firmware files from
linux-firmware repository.

Signed-off-by: Jürg Billeter <j@bitron.ch>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>