The only remaining field in struct had_stream_data is stream_type that
holds the current stream status.  Such information fits better in
struct pcm_stream_info, so move it as a boolean "running" field to be
clearer.

This allows us to get rid or had_stream_data definition and
references.

Also, the superfluous status check get removed in a couple of places
where we can call PCM helpers in anyway.
Signed-off-by: Takashi Iwai <tiwai@suse.de>