lavc/vaapi_encode: add FF_CODEC_CAP_INIT_CLEANUP caps for encoders

ff_vaapi_encode_close() is not enough to free the resources like cbs
if initialization failure happens after codec->configure (except for
vp8/vp9).

We need to call avctx->codec->close() to deallocate, otherwise memory
leak happens.

Add FF_CODEC_CAP_INIT_CLEANUP for vaapi encoders and deallocate the
resources at free_and_end inside avcodec_open2().

Reviewed-by: Timo Rothenpieler <timo@rothenpieler.org>
Signed-off-by: Linjie Fu <linjie.fu@intel.com>

libavcodec/vaapi_encode_vp8.c

@@ -257,6 +257,7 @@ AVCodec ff_vp8_vaapi_encoder = {
     .close          = &ff_vaapi_encode_close,
     .priv_class     = &vaapi_encode_vp8_class,
     .capabilities   = AV_CODEC_CAP_DELAY | AV_CODEC_CAP_HARDWARE,
+    .caps_internal  = FF_CODEC_CAP_INIT_CLEANUP,
     .defaults       = vaapi_encode_vp8_defaults,
     .pix_fmts = (const enum AVPixelFormat[]) {
         AV_PIX_FMT_VAAPI,