[PATCH] mark scsi_add_host __must_check

it seems scsi_add_host() is one of those functions that a driver really has
to check the return value of, but several forget to do this. Patch below
marks it __must_check which will cause a warning in this case (with gcc
3.4 and later)..
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

include/scsi/scsi_host.h

@@ -524,7 +524,7 @@ struct Scsi_Host {
 	container_of(d, struct Scsi_Host, shost_classdev)
 
 extern struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *, int);
-extern int scsi_add_host(struct Scsi_Host *, struct device *);
+extern int __must_check scsi_add_host(struct Scsi_Host *, struct device *);
 extern void scsi_scan_host(struct Scsi_Host *);
 extern void scsi_remove_host(struct Scsi_Host *);
 extern struct Scsi_Host *scsi_host_get(struct Scsi_Host *);