scsi: fc: Export fc_bsg_jobdone and use it in FC drivers

Export fc_bsg_jobdone so drivers can use it directly instead of doing
the round-trip via struct fc_bsg_job::job_done() and use it in the
LLDDs.  That way we can also unify the interfaces of fc_bsg_jobdone and
bsg_job_done.

As we've converted all LLDDs over to use fc_bsg_jobdone() directly, we
can remove the function pointer from struct fc_bsg_job as well.

Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>