scsi: target: core: New key must be used for moved PR

According to SPC4 5.12.8:

  e) Retain the reservation key specified in the SERVICE ACTION RESERVATION
  KEY field and associated information;

But currently sa_res_key is only used for the not existing I_T nexus. Add a
changing of the key for the existing I_T nexus the PR moved to.

Link: https://lore.kernel.org/r/20220909090425.14479-5-d.bogdanov@yadro.comReviewed-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Dmitry Bogdanov <d.bogdanov@yadro.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/target/target_core_pr.c

@@ -3440,8 +3440,6 @@ core_scsi3_emulate_pro_register_and_move(struct se_cmd *cmd, u64 res_key,
 	 *       transport protocols where port names are not required;
 	 * d) Register the reservation key specified in the SERVICE ACTION
 	 *    RESERVATION KEY field;
-	 * e) Retain the reservation key specified in the SERVICE ACTION
-	 *    RESERVATION KEY field and associated information;
 	 *
 	 * Also, It is not an error for a REGISTER AND MOVE service action to
 	 * register an I_T nexus that is already registered with the same
@@ -3463,6 +3461,12 @@ core_scsi3_emulate_pro_register_and_move(struct se_cmd *cmd, u64 res_key,
 		dest_pr_reg = __core_scsi3_locate_pr_reg(dev, dest_node_acl,
 						iport_ptr);
 		new_reg = 1;
+	} else {
+		/*
+		 * e) Retain the reservation key specified in the SERVICE ACTION
+		 *    RESERVATION KEY field and associated information;
+		 */
+		dest_pr_reg->pr_res_key = sa_res_key;
 	}
 	/*
 	 * f) Release the persistent reservation for the persistent reservation