ARM: imx: dynamically allocate imx2-wdt devices

Currently there is no platform data used in the driver.  In case this
changes and for consistency NULL is passed unused to the soc specific
functions.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
diff --git a/arch/arm/mach-imx/devices-imx21.h b/arch/arm/mach-imx/devices-imx21.h
index 61b0aa7..738dbba 100644
--- a/arch/arm/mach-imx/devices-imx21.h
+++ b/arch/arm/mach-imx/devices-imx21.h
@@ -9,6 +9,10 @@
 #include <mach/mx21.h>
 #include <mach/devices-common.h>
 
+extern const struct imx_imx2_wdt_data imx21_imx2_wdt_data __initconst;
+#define imx21_add_imx2_wdt(pdata)	\
+	imx_add_imx2_wdt(&imx21_imx2_wdt_data)
+
 extern const struct imx_imx_i2c_data imx21_imx_i2c_data __initconst;
 #define imx21_add_imx_i2c(pdata)	\
 	imx_add_imx_i2c(&imx21_imx_i2c_data, pdata)