[SCSI] add template for scsi_host_set_state()

Fixes up some warnings in the tree.
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

include/scsi/scsi_host.h

@@ -676,5 +676,6 @@ extern struct scsi_device *scsi_get_host_dev(struct Scsi_Host *);
 /* legacy interfaces */
 extern struct Scsi_Host *scsi_register(struct scsi_host_template *, int);
 extern void scsi_unregister(struct Scsi_Host *);
+extern int scsi_host_set_state(struct Scsi_Host *, enum scsi_host_state);
 
 #endif /* _SCSI_SCSI_HOST_H */