[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/ide/legacy/hd.c b/drivers/ide/legacy/hd.c
index 8f2db8d..8e05d88 100644
--- a/drivers/ide/legacy/hd.c
+++ b/drivers/ide/legacy/hd.c
@@ -652,7 +652,7 @@
 	}
 }
 
-static void do_hd_request (request_queue_t * q)
+static void do_hd_request (struct request_queue * q)
 {
 	disable_irq(HD_IRQ);
 	hd_request();