HACK Revert "h264: free the tables and uninitialize the context on flush"

This reverts commit 9eda9d3322a6ea91830a754f2edee222adae7e67.
This commit causes the flush inside the DXVA2 init to crash, so we cannot do this here.

The fix isn't required for our use-case anyway, since LAV always does a hard-flush when seeking H.264.
dxva2_vc1: fix intensity compensation condition with interlaced fields
matroskadec_haali: export mkv codec id as metadata