watchdog: update maintainers git entry

The git repository for watchdog device drivers moved.
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

MAINTAINERS

@@ -7271,7 +7271,7 @@ WATCHDOG DEVICE DRIVERS
 M:	Wim Van Sebroeck <wim@iguana.be>
 L:	linux-watchdog@vger.kernel.org
 W:	http://www.linux-watchdog.org/
-T:	git git://git.kernel.org/pub/scm/linux/kernel/git/wim/linux-2.6-watchdog.git
+T:	git git://www.linux-watchdog.org/linux-watchdog.git
 S:	Maintained
 F:	Documentation/watchdog/
 F:	drivers/watchdog/