[BLOCK] Get rid of request_queue_t typedef

Some of the code has been gradually transitioned to using the proper
struct request_queue, but there's lots left. So do a full sweet of
the kernel and get rid of this typedef and replace its uses with
the proper type.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/drivers/s390/char/tape.h b/drivers/s390/char/tape.h
index 3b52f5c..dddf8d6 100644
--- a/drivers/s390/char/tape.h
+++ b/drivers/s390/char/tape.h
@@ -188,7 +188,7 @@
 {
 	struct tape_device *	device;
 	/* Block device request queue. */
-	request_queue_t *	request_queue;
+	struct request_queue *	request_queue;
 	spinlock_t		request_queue_lock;
 
 	/* Task to move entries from block request to CCS request queue. */