block: get rid of MQ scheduler ops union

This is a remnant of when we had ops for both SQ and MQ
schedulers. Now it's just MQ, so get rid of the union.

Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/block/mq-deadline.c b/block/mq-deadline.c
index 513edef..1bd06ce 100644
--- a/block/mq-deadline.c
+++ b/block/mq-deadline.c
@@ -761,7 +761,7 @@
 #endif
 
 static struct elevator_type mq_deadline = {
-	.ops.mq = {
+	.ops = {
 		.insert_requests	= dd_insert_requests,
 		.dispatch_request	= dd_dispatch_request,
 		.prepare_request	= dd_prepare_request,