watchdog: mpc8xxx_wdt: Constify static struct watchdog_ops

The struct mpc8xxx_wdt_ops is only assigned to the ops pointer in the
watchdog_device struct, which is a pointer to const struct watchdog_ops.
Make it const to allow the compiler to put it in read-only memory.

Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20210727223042.48150-4-rikard.falkeborn@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

drivers/watchdog/mpc8xxx_wdt.c

@@ -118,7 +118,7 @@ static struct watchdog_info mpc8xxx_wdt_info = {
 	.identity = "MPC8xxx",
 };
 
-static struct watchdog_ops mpc8xxx_wdt_ops = {
+static const struct watchdog_ops mpc8xxx_wdt_ops = {
 	.owner = THIS_MODULE,
 	.start = mpc8xxx_wdt_start,
 	.ping = mpc8xxx_wdt_ping,