tty: n_tty: use output character directly

There is no point to use a local variable to store the character when we
can pass it directly. This assignment comes from era when we used to do
get_user(c, b). We no longer need this, so fix this.

Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20230827074147.2287-3-jirislaby@kernel.org


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