[SCSI] zfcp: Report FC BSG errors in correct field

The status FC_CTELS_STATUS_REJECT for all FC BSG errors is not
appropriate. Instead, report -EIO in the result field if there was a
problem in zfcp with the FC BSG request. If the request is good from
our point of view, report result 0, status FC_CTELS_STATUS_OK and let
userspace read the Accept or Reject from the payload (as documented in
scsi_bsg_fc.h).

Signed-off-by: Swen Schillig <swen@vnet.ibm.com>
Signed-off-by: Christof Schmitt <christof.schmitt@de.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>