NFC: pn533: Fix use after free

commit 770f750b upstream.

cmd was freed in pn533_dep_link_up regardless of
pn533_send_cmd_frame_async return code. Cmd is passed as argument to
pn533_in_dep_link_up_complete callback and should be freed there.
Signed-off-by: Szymon Janc <szymon.janc@tieto.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/nfc/pn533.c

@@ -1385,12 +1385,8 @@ static int pn533_dep_link_up(struct nfc_dev *nfc_dev, int target_idx,
 	rc = pn533_send_cmd_frame_async(dev, dev->out_frame, dev->in_frame,
 				dev->in_maxlen,	pn533_in_dep_link_up_complete,
 				cmd, GFP_KERNEL);
-	if (rc)
-		goto out;
-
-
-out:
-	kfree(cmd);
+	if (rc < 0)
+		kfree(cmd);
 
 	return rc;
 }