tty: tty_driver: move TTY macros to the top

So that they can be referenced in structs once converted to enums (in
the next patches).

Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20250317070046.24386-13-jirislaby@kernel.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>