Revert "avformat/wvdec: Check rate for overflow"

The code this fixes is not in release/4.1

Found-by: <mkver>
This reverts commit b81d1379.

libavformat/wvdec.c

@@ -81,7 +81,6 @@ static int wv_read_block_header(AVFormatContext *ctx, AVIOContext *pb)
     int ret;
     int rate, bpp, chan;
     uint32_t chmask, flags;
-    unsigned rate_x;
 
     wc->pos = avio_tell(pb);
 
@@ -180,7 +179,7 @@ static int wv_read_block_header(AVFormatContext *ctx, AVIOContext *pb)
             if (id & 0x40)
                 avio_skip(pb, 1);
         }
-        if (rate == -1 || rate * (uint64_t)rate_x >= INT_MAX) {
+        if (rate == -1) {
             av_log(ctx, AV_LOG_ERROR,
                    "Cannot determine custom sampling rate\n");
             return AVERROR_INVALIDDATA;