[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/paride/pd.c b/drivers/block/paride/pd.c
index 31e0148..df819f8 100644
--- a/drivers/block/paride/pd.c
+++ b/drivers/block/paride/pd.c
@@ -698,7 +698,7 @@
 
 /* end of io request engine */
 
-static void do_pd_request(request_queue_t * q)
+static void do_pd_request(struct request_queue * q)
 {
 	if (pd_req)
 		return;