Similar to ixgbe, when an interface is part of a namespace it is
possible that igb_close() may be called while __igb_shutdown() is
running which ends up in a double free WARN and/or a BUG in
free_msi_irqs().

Extend the rtnl_lock() to protect the call to netif_device_detach() and
igb_clear_interrupt_scheme() in __igb_shutdown() and check for
netif_device_present() to avoid calling igb_clear_interrupt_scheme() a
second time in igb_close().

Also extend the rtnl lock in igb_resume() to netif_device_attach().
Signed-off-by: Todd Fujinaka <todd.fujinaka@intel.com>
Acked-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>