avcodec/flac_parser: Don't allocate array separately

avcodec/flac_parser: Don't allocate array separately

The FLACHeaderMarker structure contained a pointer to an array of int;
said array was always allocated and freed at the same time as its
referencing FLACHeaderMarker; the pointer was never modified to point to
a different array and each FLACHeaderMarker had its own unique array.
Furthermore, all these arrays had a constant size. Therefore include
this array in the FLACHeaderMarker struct.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>