[SCSI] fc_transport: add target driver support

This adds minimum target driver support like the srp transport does:

- fc_remote_port_{rolechg,delete} calls
scsi_tgt_it_nexus_{create,destroy} for target drivers.

- add callbacks to notify target drivers of the nexus and tmf
operation results to fc_function_template.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

include/scsi/scsi_transport_fc.h

@@ -589,6 +589,10 @@ struct fc_function_template {
 	int	(*vport_disable)(struct fc_vport *, bool);
 	int  	(*vport_delete)(struct fc_vport *);
 
+	/* target-mode drivers' functions */
+	int     (* tsk_mgmt_response)(struct Scsi_Host *, u64, u64, int);
+	int     (* it_nexus_response)(struct Scsi_Host *, u64, int);
+
 	/* allocation lengths for host-specific data */
 	u32	 			dd_fcrport_size;
 	u32	 			dd_fcvport_size;