ALSA: fireworks: fix memory leak of response buffer at error path

commit c3b55e2e upstream.

After allocating memory object for response buffer, ALSA fireworks
driver has leak of the memory object at error path.

This commit releases the object at the error path.

Fixes: 7d3c1d59('ALSA: fireworks: delayed registration of sound card')
Cc: <stable@vger.kernel.org> # v4.7+
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

sound/firewire/fireworks/fireworks.c

@@ -301,6 +301,8 @@ do_registration(struct work_struct *work)
 	snd_efw_transaction_remove_instance(efw);
 	snd_efw_stream_destroy_duplex(efw);
 	snd_card_free(efw->card);
+	kfree(efw->resp_buf);
+	efw->resp_buf = NULL;
 	dev_info(&efw->unit->device,
 		 "Sound card registration failed: %d\n", err);
 }