[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/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 6746c29..964e516 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -241,7 +241,7 @@
  * do_blkif_request
  *  read a block; request is in a request queue
  */
-static void do_blkif_request(request_queue_t *rq)
+static void do_blkif_request(struct request_queue *rq)
 {
 	struct blkfront_info *info = NULL;
 	struct request *req;
@@ -287,7 +287,7 @@
 
 static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size)
 {
-	request_queue_t *rq;
+	struct request_queue *rq;
 
 	rq = blk_init_queue(do_blkif_request, &blkif_io_lock);
 	if (rq == NULL)