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>

Author: Jiri Slaby (SUSE)

drivers/tty/n_tty.c

@@ -2373,8 +2373,7 @@ static ssize_t n_tty_write(struct tty_struct *tty, struct file *file,
 				nr -= num;
 				if (nr == 0)
 					break;
-				c = *b;
-				if (process_output(c, tty) < 0)
+				if (process_output(*b, tty) < 0)
 					break;
 				b++; nr--;
 			}