include: add enum for chroma location
include: add enum for chroma location

This lets us handle chroma location correctly further down the
rendering chain (even if in general things can be assumed by just
the video track's format).

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

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