[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/lguest_blk.c b/drivers/block/lguest_blk.c
index 1634c2d..5b79d07 100644
--- a/drivers/block/lguest_blk.c
+++ b/drivers/block/lguest_blk.c
@@ -137,7 +137,7 @@
 	lguest_send_dma(bd->phys_addr, &ping);
 }
 
-static void do_lgb_request(request_queue_t *q)
+static void do_lgb_request(struct request_queue *q)
 {
 	struct blockdev *bd;
 	struct request *req;