[SCSI] fcoe: split out per interface setup

fcoe_netdev_config() is called during initialization of a libfc instance.
Much of what was there only needs to be done once for each net_device.
The same goes for the corresponding cleanup.

The FIP controller initialization is moved to interface creation time.
Otherwise it will keep getting re-initialized for every VN_Port once NPIV is
enabled.

fcoe_if_destroy() has some reordering to deal with the changes.  Receives are
not stopped until after fcoe_interface_put() is called, but transmits must be
stopped before.  So there is some care to stop libfc transmits and the
transmit backlog timer, then call fcoe_interface_put which will stop receives
and cleanup the FIP controller, then the receive queues can be cleaned and the
port freed.

Signed-off-by: Chris Leech <christopher.leech@intel.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>