block: remove per-queue plugging

Code has been converted over to the new explicit on-stack plugging,
and delay users have been converted to use the new API for that.
So lets kill off the old plugging along with aops->sync_page().

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
diff --git a/fs/direct-io.c b/fs/direct-io.c
index b044705..df709b3 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -1110,11 +1110,8 @@
 	    ((rw & READ) || (dio->result == dio->size)))
 		ret = -EIOCBQUEUED;
 
-	if (ret != -EIOCBQUEUED) {
-		/* All IO is now issued, send it on its way */
-		blk_run_address_space(inode->i_mapping);
+	if (ret != -EIOCBQUEUED)
 		dio_await_completion(dio);
-	}
 
 	/*
 	 * Sync will always be dropping the final ref and completing the