[WATCHDOG] watchdog_info constify

make the watchdog_info struct const where possible.

Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

diff --git a/drivers/watchdog/adx_wdt.c b/drivers/watchdog/adx_wdt.c
index 9d7d155..a5ca7a6 100644
--- a/drivers/watchdog/adx_wdt.c
+++ b/drivers/watchdog/adx_wdt.c
@@ -37,7 +37,7 @@
 	spinlock_t lock;
 };
 
-static struct watchdog_info adx_wdt_info = {
+static const struct watchdog_info adx_wdt_info = {
 	.identity = "Avionic Design Xanthos Watchdog",
 	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
 };