Merge branch 'net-inline-rollback_registered-functions'

After recent changes to the error path of register_netdevice()
we no longer need a version of unregister_netdevice_many() which
does not set net_todo. We can inline the rollback_registered()
functions into respective unregister_netdevice() calls.

Link: https://lore.kernel.org/r/20210119202521.3108236-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>