Revert "Do not decode RV30 files if the extradata is too small"

This commit is plain wrong, theres no reason to error out at this point nor is the
error value guranteed to be negative as it should be

This reverts commit 289c600.

libavcodec/rv30.c

@@ -256,7 +256,6 @@ static av_cold int rv30_decode_init(AVCodecContext *avctx)
     if(avctx->extradata_size - 8 < (r->rpr - 1) * 2){
         av_log(avctx, AV_LOG_ERROR, "Insufficient extradata - need at least %d bytes, got %d\n",
                6 + r->rpr * 2, avctx->extradata_size);
-        return EINVAL;
     }
     r->parse_slice_header = rv30_parse_slice_header;
     r->decode_intra_types = rv30_decode_intra_types;