[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/bfin_wdt.c b/drivers/watchdog/bfin_wdt.c
index 31dc7a6..472be10 100644
--- a/drivers/watchdog/bfin_wdt.c
+++ b/drivers/watchdog/bfin_wdt.c
@@ -390,7 +390,7 @@
 	.resume    = bfin_wdt_resume,
 };
 
-static struct file_operations bfin_wdt_fops = {
+static const struct file_operations bfin_wdt_fops = {
 	.owner    = THIS_MODULE,
 	.llseek   = no_llseek,
 	.write    = bfin_wdt_write,