watchdog: add support for the Synopsys DesignWare WDT

The Synopsys DesignWare watchdog is found in several ARM based systems
and provides a choice of 16 timeout periods depending on the clock
input.  The watchdog cannot be disabled once started.

Signed-off-by: Jamie Iles <jamie@jamieiles.com>
Acked-by: Viresh Kumar <viresh.kumar@st.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index ed26f70..b2ddff7 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -37,6 +37,7 @@
 obj-$(CONFIG_KS8695_WATCHDOG) += ks8695_wdt.o
 obj-$(CONFIG_S3C2410_WATCHDOG) += s3c2410_wdt.o
 obj-$(CONFIG_SA1100_WATCHDOG) += sa1100_wdt.o
+obj-$(CONFIG_DW_WATCHDOG) += dw_wdt.o
 obj-$(CONFIG_MPCORE_WATCHDOG) += mpcore_wdt.o
 obj-$(CONFIG_EP93XX_WATCHDOG) += ep93xx_wdt.o
 obj-$(CONFIG_PNX4008_WATCHDOG) += pnx4008_wdt.o