decklink: Fix crash when probing without driver
If there is no decklink hardware/driver, the devices list is empty (NULL), so this needs to be checked before iterating over the list.
Due to an influx of spam, we have had to impose restrictions on new accounts. Please see this wiki page for instructions on how to get full permissions. Sorry for the inconvenience.
If there is no decklink hardware/driver, the devices list is empty (NULL), so this needs to be checked before iterating over the list.