[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/z2ram.c b/drivers/block/z2ram.c
index e40fa98..2d5853c 100644
--- a/drivers/block/z2ram.c
+++ b/drivers/block/z2ram.c
@@ -67,7 +67,7 @@
 static struct block_device_operations z2_fops;
 static struct gendisk *z2ram_gendisk;
 
-static void do_z2_request(request_queue_t *q)
+static void do_z2_request(struct request_queue *q)
 {
 	struct request *req;
 	while ((req = elv_next_request(q)) != NULL) {