pipeline: raspberrypi: Create empty control lists correctly

When the pipeline handler start() method is supplied with a NULL list
of controls, we send an empty control list to the IPA. When the IPA is
running in isolated mode the control list goes through the data
serializer, for which it must be marked correctly as a list of
"controls::controls", otherwise the IPA process will abort.

The IPA has a similar problem returning a control list in its
configure() method. We must be careful to initialise it properly even
when empty.

Signed-off-by: David Plowman <david.plowman@raspberrypi.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Naushir Patuck <naush@raspberrypi.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
2 files changed