[WATCHDOG] constify function pointer tables

"static struct file_operations" should be
"static const struct file_operations".

Signed-off-by: Jan Engelhardt <jengelh@computergmbh.de>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

diff --git a/drivers/watchdog/mtx-1_wdt.c b/drivers/watchdog/mtx-1_wdt.c
index dcfd401..9845174 100644
--- a/drivers/watchdog/mtx-1_wdt.c
+++ b/drivers/watchdog/mtx-1_wdt.c
@@ -180,7 +180,7 @@
 	return count;
 }
 
-static struct file_operations mtx1_wdt_fops = {
+static const struct file_operations mtx1_wdt_fops = {
 	.owner 		= THIS_MODULE,
 	.llseek		= no_llseek,
 	.ioctl		= mtx1_wdt_ioctl,