Include <stdint.h> in include/watchdog.h.

Previously, the int types used in the watchdog_trace() function
signature were not being included properly.

BUG=none
BRANCH=none
TEST=make buildall -j

Change-Id: Ib4666285c314cbdb101e3ba602e4f27540a1346c
Reviewed-on: https://chromium-review.googlesource.com/448345
Commit-Ready: Jeff Andersen <jeffandersen@google.com>
Tested-by: Jeff Andersen <jeffandersen@google.com>
Reviewed-by: Carl Hamilton <carlh@chromium.org>
Reviewed-by: Vadim Bendebury <vbendeb@chromium.org>

include/watchdog.h

@@ -8,6 +8,8 @@
 #ifndef __CROS_EC_WATCHDOG_H
 #define __CROS_EC_WATCHDOG_H
 
+#include <stdint.h>
+
 /**
  * Initialize the watchdog.
  *