watchdog: Export touch_softlockup_watchdog

There are modules that rely on it:

  ERROR: "touch_softlockup_watchdog" [drivers/video/nvidia/nvidiafb.ko] undefined!

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
LKML-Reference: <1273713674-8434-1-git-send-regression-fweisbec@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

kernel/watchdog.c

@@ -124,6 +124,7 @@ void touch_softlockup_watchdog(void)
 {
 	__get_cpu_var(watchdog_touch_ts) = 0;
 }
+EXPORT_SYMBOL(touch_softlockup_watchdog);
 
 void touch_all_softlockup_watchdogs(void)
 {