scsi: Remove Scsi_Host.uspace_req_q

A patch I wrote myself several years ago removed SCSI target support
from the code under drivers/scsi. That patch removed the code that sets
uspace_req_q to a non-NULL value. Hence also remove the code that
depends on uspace_req_q != NULL.

References: commit 0664652513 ("tgt: removal")
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

include/scsi/scsi_host.h

@@ -691,12 +691,6 @@ struct Scsi_Host {
 	unsigned int prot_capabilities;
 	unsigned char prot_guard_type;
 
-	/*
-	 * q used for scsi_tgt msgs, async events or any other requests that
-	 * need to be processed in userspace
-	 */
-	struct request_queue *uspace_req_q;
-
 	/* legacy crap */
 	unsigned long base;
 	unsigned long io_port;