drm/i915/hdmi: fix hdmi audio state readout

Check the correct bit for audio. Seems like a copy-paste error from the
start:

commit 9ed109a7
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Thu Apr 24 23:54:52 2014 +0200

    drm/i915: Track has_audio in the pipe config
Reported-by: NMartin Andersen <martin.x.andersen@gmail.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=82756
Cc: stable@vger.kernel.org # 3.16+
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/intel_hdmi.c

@@ -732,7 +732,7 @@ static void intel_hdmi_get_config(struct intel_encoder *encoder,
 	if (tmp & HDMI_MODE_SELECT_HDMI)
 		pipe_config->has_hdmi_sink = true;
 
-	if (tmp & HDMI_MODE_SELECT_HDMI)
+	if (tmp & SDVO_AUDIO_ENABLE)
 		pipe_config->has_audio = true;
 
 	if (!HAS_PCH_SPLIT(dev) &&