[SCSI] libfcoe: Allow FIP to be disabled by the driver

Allow FIP to be disabled by the driver for devices
that want to use libfcoe in non-FIP mode.

The driver merely sets the fcoe_ctlr mode to the state which
should be entered when the link comes up.  The default is auto.
No change is needed for fcoe.c which uses auto mode.

Signed-off-by: Joe Eykholt <jeykholt@cisco.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>