fix dts spdif output regression

dts spdif output was broken by the switch over to the new filter
API.

  * dtstofloat32 should only take control if there is _no_ spdif
    output requested otherwise the decoded stream ends up on the
    spdif device
Signed-off-by: Rémi Denis-Courmont <remi@remlab.net>

modules/audio_filter/converter/dtstofloat32.c

@@ -325,7 +325,9 @@ static int OpenFilter( vlc_object_t *p_this )
     filter_sys_t *p_sys;
     int i_ret;
 
-    if( p_filter->fmt_in.i_codec != VLC_CODEC_DTS  )
+    if( p_filter->fmt_in.i_codec != VLC_CODEC_DTS ||
+        p_filter->fmt_out.audio.i_format == VLC_CODEC_SPDIFB ||
+        p_filter->fmt_out.audio.i_format == VLC_CODEC_SPDIFL )
     {
         return VLC_EGENERIC;
     }