lavc/libkvazaar: switch to ff_alloc_packet2.

ff_alloc_packet have been deprecated, switch to use the
ff_alloc_packet2.
Signed-off-by: Jun Zhao <jun.zhao@intel.com>
Reviewed-by: Arttu Ylä-Outinen <arttu.yla-outinen@tut.fi>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/libkvazaar.c

@@ -231,7 +231,7 @@ static int libkvazaar_encode(AVCodecContext *avctx,
         kvz_data_chunk *chunk = NULL;
         uint64_t written = 0;
 
-        retval = ff_alloc_packet(avpkt, len_out);
+        retval = ff_alloc_packet2(avctx, avpkt, len_out, len_out);
         if (retval < 0) {
             av_log(avctx, AV_LOG_ERROR, "Failed to allocate output packet.\n");
             goto done;