drm/i915/audio: Hook up component bindings even if displays are disabled

If the display has been disabled by modparam, we still want to connect
together the HW bits and bobs with the associated drivers so that we can
continue to manage their runtime power gating.

Fixes: 10810944

 ("drm/i915: Check num_pipes before initializing audio component")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Elaine Wang <elaine.wang@intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180817100241.4628-1-chris@chris-wilson.co.uk