n_tty: Remove stale read lock comment

The stale comment refers to lock behavior which was eliminated in
commit 6d76bd26,
n_tty: Make N_TTY ldisc receive path lockless.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/n_tty.c

@@ -2248,8 +2248,6 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
 				nr--;
 			}
 
-			/* The copy function takes the read lock and handles
-			   locking internally for this case */
 			uncopied = copy_from_read_buf(tty, &b, &nr);
 			uncopied += copy_from_read_buf(tty, &b, &nr);
 			if (uncopied) {