scsi: remove ->change_queue_type method

Since we got rid of ordered tag support in 2010 the prime use case of
switching on and off ordered tags has been obsolete.  The other function
of enabling/disabling tagging entirely has only been correctly implemented
by the 53c700 driver and isn't generally useful.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com
Reviewed-by: Hannes Reinecke <hare@suse.de>

include/scsi/libsas.h

@@ -693,7 +693,6 @@ extern int sas_queuecommand(struct Scsi_Host * ,struct scsi_cmnd *);
 extern int sas_target_alloc(struct scsi_target *);
 extern int sas_slave_configure(struct scsi_device *);
 extern int sas_change_queue_depth(struct scsi_device *, int new_depth);
-extern int sas_change_queue_type(struct scsi_device *, int qt);
 extern int sas_bios_param(struct scsi_device *,
 			  struct block_device *,
 			  sector_t capacity, int *hsc);

include/scsi/scsi_host.h

@@ -277,19 +277,6 @@ struct scsi_host_template {
 	 */
 	int (* change_queue_depth)(struct scsi_device *, int);
 
-	/*
-	 * Fill in this function to allow the changing of tag types
-	 * (this also allows the enabling/disabling of tag command
-	 * queueing).  An error should only be returned if something
-	 * went wrong in the driver while trying to set the tag type.
-	 * If the driver doesn't support the requested tag type, then
-	 * it should set the closest type it does support without
-	 * returning an error.  Returns the actual tag type set.
-	 *
-	 * Status: OPTIONAL
-	 */
-	int (* change_queue_type)(struct scsi_device *, int);
-
 	/*
 	 * This function determines the BIOS parameters for a given
 	 * harddisk.  These tend to be numbers that are made up by

include/scsi/scsi_tcq.h

@@ -15,9 +15,6 @@
 
 
 #ifdef CONFIG_BLOCK
-
-int scsi_change_queue_type(struct scsi_device *sdev, int tag_type);
-
 /**
  * scsi_get_tag_type - get the type of tag the device supports
  * @sdev:	the scsi device