Both callers use btrfs_header_nritems to feed the max argument.  Remove
the argument and let generic_bin_search call it itself.
Reviewed-by: NNikolay Borisov <nborisov@suse.com>
Signed-off-by: NMarcos Paulo de Souza <mpdesouza@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>