fs: reorder i_state bits

so that we can use the first bits to derive unique addresses from
i_state.

Link: https://lore.kernel.org/r/20240823-work-i_state-v3-2-5cd5fd207a57@kernel.org


Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>