libvlc.h: Remove --audio-type which was never used according to grep

src/libvlc.h

@@ -295,11 +295,6 @@ static char *ppsz_align_descriptions[] =
     "Choose the programs to select by giving a comma-separated list of " \
     "SIDs.")
 
-#define INPUT_AUDIO_TEXT N_("Choose audio")
-#define INPUT_AUDIO_LONGTEXT N_( \
-    "Give the default type of audio you want to use in a DVD. " \
-    "(Developers only)")
-
 #define INPUT_CHAN_TEXT N_("Choose audio channel")
 #define INPUT_CHAN_LONGTEXT N_( \
     "Give the stream number of the audio channel you want to use in a DVD " \
@@ -936,8 +931,6 @@ vlc_module_begin();
                  INPUT_PROGRAM_TEXT, INPUT_PROGRAM_LONGTEXT, VLC_TRUE );
     add_string( "programs", "", NULL,
                 INPUT_PROGRAMS_TEXT, INPUT_PROGRAMS_LONGTEXT, VLC_FALSE );
-    add_integer( "audio-type", -1, NULL,
-                 INPUT_AUDIO_TEXT, INPUT_AUDIO_LONGTEXT, VLC_TRUE );
     add_integer( "audio-channel", -1, NULL,
                  INPUT_CHAN_TEXT, INPUT_CHAN_LONGTEXT, VLC_FALSE );
     add_integer( "spu-channel", -1, NULL,