[SCSI] libfc: Add target reset flag to FCP header file

While the target reset task management function has been deprecated in
newer specs, it is still in use by SCSI FC drivers and there is no
real replacement. Add the target reset flag to the FCP header file to
allow usage of this definition in SCSI FC drivers.

Reviewed-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>