btrfs: remove the redundant parameter level in btrfs_bin_search()

All callers pass the eb::level so we can get read it directly inside the
btrfs_bin_search and key_search.

This is inspired by the work of Marek in U-boot.

CC: Marek Behun <marek.behun@nic.cz>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 02ebdd9..0254e8d 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -3816,8 +3816,7 @@ static int drop_objectid_items(struct btrfs_trans_handle *trans,
 
 		found_key.offset = 0;
 		found_key.type = 0;
-		ret = btrfs_bin_search(path->nodes[0], &found_key, 0,
-				       &start_slot);
+		ret = btrfs_bin_search(path->nodes[0], &found_key, &start_slot);
 		if (ret < 0)
 			break;