watchdog: Xen watchdog driver

While the hypervisor change adding SCHEDOP_watchdog support included a
daemon to make use of the new functionality, having a kernel driver
for /dev/watchdog so that user space code doesn't need to distinguish
non-Xen and Xen seems to be preferable.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index b037f3d..d520bf9 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -150,6 +150,9 @@
 
 # XTENSA Architecture
 
+# Xen
+obj-$(CONFIG_XEN_WDT) += xen_wdt.o
+
 # Architecture Independant
 obj-$(CONFIG_WM831X_WATCHDOG) += wm831x_wdt.o
 obj-$(CONFIG_WM8350_WATCHDOG) += wm8350_wdt.o