btrfs: cleanup: use already calculated value in btrfs_should_throttle_delayed_refs()

Signed-off-by: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/extent-tree.c

@@ -2826,7 +2826,7 @@ int btrfs_should_throttle_delayed_refs(struct btrfs_trans_handle *trans,
 	smp_mb();
 	avg_runtime = fs_info->avg_delayed_ref_runtime;
 	val = num_entries * avg_runtime;
-	if (num_entries * avg_runtime >= NSEC_PER_SEC)
+	if (val >= NSEC_PER_SEC)
 		return 1;
 	if (val >= NSEC_PER_SEC / 2)
 		return 2;