scsi: don't allow setting of queue_depth bigger than can_queue

We won't ever queue more commands than the host allows.  Instead of
letting drivers either reject or ignore this case handle it in
common code.  Note that various driver use internal constant or
variables that are assigned to both shost->can_queue and checked
in ->change_queue_depth - I did remove those checks as well.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Reviewed-by: Hannes Reinecke <hare@suse.de>
diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index 98a3035..8d13a19 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -2410,14 +2410,8 @@
 static int
 srp_change_queue_depth(struct scsi_device *sdev, int qdepth, int reason)
 {
-	struct Scsi_Host *shost = sdev->host;
-	int max_depth;
-
-	max_depth = shost->can_queue;
 	if (!sdev->tagged_supported)
-		max_depth = 1;
-	if (qdepth > max_depth)
-		qdepth = max_depth;
+		qdepth = 1;
 	scsi_adjust_queue_depth(sdev, qdepth);
 	return sdev->queue_depth;
 }