watchdog: Fix warning

This seems to have popped up after the recent merges:

drivers/watchdog/w83697ug_wdt.c: In function ‘w83697ug_select_wd_register’:
drivers/watchdog/w83697ug_wdt.c:105: warning: ‘return’ with a value, in function returning void
Signed-off-by: NAlan Cox <alan@redhat.com>
Acked-by: NWim Van Sebroeck <wim@iguana.be>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/watchdog/w83697ug_wdt.c

@@ -102,7 +102,7 @@ static void w83697ug_select_wd_register(void)
 
 	} else {
 		printk(KERN_ERR PFX "No W83697UG/UF could be found\n");
-		return -EIO;
+		return;
 	}
 
 	outb_p(0x07, WDT_EFER); /* point to logical device number reg */