linux-phytec-fsl

6lowpan: ndisc: fix double read unlock

This patch removes a double unlock case to accessing neighbour private
data.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alexander Aring <aar@pengutronix.de>
Reviewed-by: Stefan Schmidt <stefan@osg.samsung.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>