lavd/vfwcap: Pass pointers to int instead of long to av_parse_video_size().

Fixes the following warnings:
libavdevice/vfwcap.c:331:35: warning: passing argument 1 of 'av_parse_video_size' from incompatible pointer type
libavdevice/vfwcap.c:331:59: warning: passing argument 2 of 'av_parse_video_size' from incompatible pointer type

Reported-by: Reino Wijnsma

libavdevice/vfwcap.c

@@ -328,11 +328,14 @@ static int vfw_read_header(AVFormatContext *s)
     }
 
     if (ctx->video_size) {
-        ret = av_parse_video_size(&bi->bmiHeader.biWidth, &bi->bmiHeader.biHeight, ctx->video_size);
+        int w, h;
+        ret = av_parse_video_size(&w, &h, ctx->video_size);
         if (ret < 0) {
             av_log(s, AV_LOG_ERROR, "Couldn't parse video size.\n");
             goto fail;
         }
+        bi->bmiHeader.biWidth  = w;
+        bi->bmiHeader.biHeight = h;
     }
 
     if (0) {