Staging: intel_sst: fix memory leak

The original code set "str_info->decode_ibuf" to NULL so the kfree() is
no-op.

Signed-off-by: Dan Carpenter <[e-mail]>
Acked-by: Harsha Priya <[e-mail]>
Acked-by: Alan Cox <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/staging/intel_sst/intel_sst_stream_encoded.c

···
 	dbufs->output_bytes_produced = total_output;
 	str_info->status = str_info->prev;
 	str_info->prev = STREAM_DECODE;
-	str_info->decode_ibuf = NULL;
 	kfree(str_info->decode_ibuf);
+	str_info->decode_ibuf = NULL;
 	return retval;
 }