hevc_ps: make sure failing to decode an SPS always returns an error

Some of the goto err clauses do not set the error code. It seems better
to fall back on INVALIDDATA instead of adding it everywhere explicitly.

libavcodec/hevc_ps.c

@@ -965,7 +965,7 @@ int ff_hevc_parse_sps(HEVCSPS *sps, GetBitContext *gb, unsigned int *sps_id,
     return 0;
 
 err:
-    return ret;
+    return ret < 0 ? ret : AVERROR_INVALIDDATA;
 }
 
 int ff_hevc_decode_nal_sps(GetBitContext *gb, AVCodecContext *avctx,