ALSA: hda - Initialize output paths with current active states

Set path->active flag at the path creation time and let the paths
initialized according to the current path->active state in
set_output_and_unmute().  This allows to modify the active flag of
some output paths dynamically, e.g. switching the front output route
with or without aamix like patch_via.c.

Signed-off-by: Takashi Iwai <tiwai@suse.de>