We can determine that the pipe was shut down from pipe<0, so there's
no point in duplicating that information as 'hdmi_connected'.

v2: Use pipe<0 instead of port<0 as we'll want to do per-port
    PCM devices later
    Initialize pipe to -1 to inidicate inactive initial state

Cc: Takashi Iwai <tiwai@suse.de>
Cc: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170427160231.13337-7-ville.syrjala@linux.intel.comReviewed-by: Takashi Iwai <tiwai@suse.de>