[SCSI] libfc: eliminate disc->event

There was no need to have the discovery status stored in struct fc_disc.

Change fc_disc_done() to take the discovery status as an argument
and just pass it on to the discovery callback.

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>