sink: force suspend/resume on passthrough transitions

sink: force suspend/resume on passthrough transitions

A race condition prevents the AES non-audio bit from being set
when enabling IEC61937 passthrough on resume with no sink-input
connected (pa_sink_is_passthrough returns false). The non-audio
bit should really be set when opening the sink.

Force the sink to suspend/resume when actually entering passthrough
mode, and likewise force a suspend-resume on leaving passthrough mode.

Tested with E-AC3 streams which do need the AES bit set for my
Onkyon receiver to detect the format instead of playing it as
PCM.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>