VGMStream: Fix memory leak

Thanks to upstream VGMStream for fixing this in the Audacious plugin,
which I derived this code from in the first place, which explains the
memory leak getting in.

Signed-off-by: Christopher Snowhill <kode54@gmail.com>

Plugins/vgmstream/vgmstream/VGMInterface.m

@@ -70,6 +70,7 @@ static void vfs_close(libstreamfile_t* libsf) {
 	if(libsf->user_data) {
 		vfs_priv_t* priv = (vfs_priv_t*)libsf->user_data;
 		CFBridgingRelease(priv->infile);
+		free(priv);
 	}
 	free(libsf);
 }