mkv: we don't need to prepare playback when jumping from Chapter commands
mkv: we don't need to prepare playback when jumping from Chapter commands

it is done in the Seek with the provided virtual_chapter

Signed-off-by: Jean-Baptiste Kempf <7b85a41a628204b76aba4326273a3ccc74bd009a@videolan.org>

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