[WATCHDOG] Add support for WM831x watchdog

The WM831x series of devices provide a watchdog with configurable
behaviour on timer expiry.

Currently this driver support refreshes via a register or GPIO line and
autonomous refreshes from a hardware source (eg, a clock).

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index e1784a6..348b3b8 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -141,5 +141,6 @@
 # XTENSA Architecture
 
 # Architecture Independant
+obj-$(CONFIG_WM831X_WATCHDOG) += wm831x_wdt.o
 obj-$(CONFIG_WM8350_WATCHDOG) += wm8350_wdt.o
 obj-$(CONFIG_SOFT_WATCHDOG) += softdog.o