IPoIB: Clean up if posting receives fails

If posting receives in ipoib_ib_dev_open() fails, call
ipoib_ib_dev_stop() to move the device's QP back to the RESET state so
that we can try again later.

Signed-off-by: Eli Cohen <eli@mellanox.co.il>
Signed-off-by: Michael S. Tsirkin <mst@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>