codec/vpx.c: do not leak memory.
codec/vpx.c: do not leak memory.

Signed-off-by: Ilkka Ollakka <88b345e2e0969920adc1eaa21d1a29b223865bcf@videolan.org>

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