tty_audit: make tty pointers in exposed functions const

Both tty_audit_add_data() and tty_audit_tiocsti() need only to read from
the tty struct, so make the tty parameters of them both const. This
aids the compiler a bit.

Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20230621101611.10580-6-jirislaby@kernel.org


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