fs: kill 'nr_pages' argument from wakeup_flusher_threads()

Everybody is passing in 0 now, let's get rid of the argument.

Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

fs/sync.c

@@ -108,7 +108,7 @@ SYSCALL_DEFINE0(sync)
 {
 	int nowait = 0, wait = 1;
 
-	wakeup_flusher_threads(0, WB_REASON_SYNC);
+	wakeup_flusher_threads(WB_REASON_SYNC);
 	iterate_supers(sync_inodes_one_sb, NULL);
 	iterate_supers(sync_fs_one_sb, &nowait);
 	iterate_supers(sync_fs_one_sb, &wait);