After commit aa626da947e9 ("iavf: Detach device during reset task")
the device is detached during reset task and re-attached at its end.
The problem occurs when reset task fails because Tx queues are
restarted during device re-attach and this leads later to a crash.
To resolve this issue properly close the net device in cause of
failure in reset task to avoid restarting of tx queues at the end.
Also replace the hacky manipulation with IFF_UP flag by device close
that clears properly both IFF_UP and __LINK_STATE_START flags.
In these case iavf_close() does not do anything because the adapter
state is already __IAVF_DOWN.