demux_chained: add missing vlc_mutex_init()/vlc_mutex_destroy()
demux_chained: add missing vlc_mutex_init()/vlc_mutex_destroy()

xkfz007/vlc,xkfz007/vlc,xkfz007/vlc,xkfz007/vlc,xkfz007/vlc,xkfz007/vlc,xkfz007/vlc