Cast away signedness warning

source/libvpx/vp9/vp9_dx_iface.c

 /*
  *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 188 matching lines @@
 
   return VPX_CODEC_OK;
 }
 
 static vpx_codec_err_t vp9_get_si(vpx_codec_alg_priv_t    *ctx,
                                   vpx_codec_stream_info_t *si) {
   const size_t sz = (si->sz >= sizeof(vp9_stream_info_t))
                        ? sizeof(vp9_stream_info_t)
                        : sizeof(vpx_codec_stream_info_t);
   memcpy(si, &ctx->si, sz);
-  si->sz = sz;
+  si->sz = (unsigned int)sz;
 
   return VPX_CODEC_OK;
 }
 
 
 static vpx_codec_err_t update_error_state(vpx_codec_alg_priv_t *ctx,
                            const struct vpx_internal_error_info *error) {
   if (error->error_code)
     ctx->base.err_detail = error->has_detail ? error->detail : NULL;
 
@@ skipping 481 matching lines @@
   { // NOLINT
     /* encoder functions */
     NOT_IMPLEMENTED,
     NOT_IMPLEMENTED,
     NOT_IMPLEMENTED,
     NOT_IMPLEMENTED,
     NOT_IMPLEMENTED,
     NOT_IMPLEMENTED
   }
 };