tty: const: constify remaining tty_operations

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/char/epca.c b/drivers/char/epca.c
index dde5134..17b044a 100644
--- a/drivers/char/epca.c
+++ b/drivers/char/epca.c
@@ -935,7 +935,7 @@
 	return 0;
 }
 
-static struct tty_operations info_ops = {
+static const struct tty_operations info_ops = {
 	.open = info_open,
 	.ioctl = info_ioctl,
 };