misc: Fix resource leak when the ioctl is failing
misc: Fix resource leak when the ioctl is failing

Fixes: Coverity CID 1040759

geosphere/osmo-bts,telenoobie/osmo-bts,telenoobie/osmo-bts,osmocom/osmo-bts,telenoobie/osmo-bts,geosphere/osmo-bts,telenoobie/osmo-bts,geosphere/osmo-bts,osmocom/osmo-bts,geosphere/osmo-bts,osmocom/osmo-bts