player: restore associated video loading

vlc_player_AddAssociatedMedia() was only accepting audio and spu.

include/vlc_player.h

@@ -879,7 +879,7 @@ vlc_player_ToggleRecording(vlc_player_t *player)
  * Add an associated (or external) media to the current media
  *
  * @param player locked player instance
- * @param cat AUDIO_ES or SPU_ES
+ * @param cat SPU_ES or UNKNOWN_ES
  * @param uri absolute uri of the external media
  * @param select true to select the track of this external media
  * @param notify true to notify the OSD

src/player/player.c

@@ -1060,14 +1060,12 @@ vlc_player_AddAssociatedMedia(vlc_player_t *player,
     enum slave_type type;
     switch (cat)
     {
-        case AUDIO_ES:
-            type = SLAVE_TYPE_GENERIC;
-            break;
         case SPU_ES:
             type = SLAVE_TYPE_SPU;
             break;
         default:
-            return VLC_EGENERIC;
+            type = SLAVE_TYPE_GENERIC;
+            break;
     }
 
     if (check_ext && type == SLAVE_TYPE_SPU && !subtitles_Filter(uri))