wavpack: remove the subframes codec cap

The decoder always consumes full packets.

libavcodec/wavpack.c

@@ -1289,6 +1289,6 @@ AVCodec ff_wavpack_decoder = {
     .close          = wavpack_decode_end,
     .decode         = wavpack_decode_frame,
     .flush          = wavpack_decode_flush,
-    .capabilities   = CODEC_CAP_SUBFRAMES | CODEC_CAP_DR1,
+    .capabilities   = CODEC_CAP_DR1,
     .long_name      = NULL_IF_CONFIG_SMALL("WavPack"),
 };