watchdog: fix watchdog-test.c build warning

Fix compiler warning by making the function static:

Documentation/watchdog/src/watchdog-test.c:34:6: warning: no previous prototype for 'term'

Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
diff --git a/Documentation/watchdog/src/watchdog-test.c b/Documentation/watchdog/src/watchdog-test.c
index 73ff5cc..3da8229 100644
--- a/Documentation/watchdog/src/watchdog-test.c
+++ b/Documentation/watchdog/src/watchdog-test.c
@@ -31,7 +31,7 @@
  * or "-e" to enable the card.
  */
 
-void term(int sig)
+static void term(int sig)
 {
     close(fd);
     fprintf(stderr, "Stopping watchdog ticks...\n");