imx31: add watchdog device on litekit board.

This patch adds support for SoC build-in watchdog device on litekit
board.

Signed-off-by: Vladimir Zapolskiy <[e-mail]>
Cc: Uwe Kleine-König <[e-mail]>
Cc: Sascha Hauer <[e-mail]>
Signed-off-by: Sascha Hauer <[e-mail]>

arch/arm/mach-mx3/mx31lite-db.c

···
 	mxc_register_device(&mxcsdhc_device0, &mmc_pdata);
 	mxc_register_device(&mxc_spi_device0, &spi0_pdata);
 	platform_device_register(&litekit_led_device);
+	mxc_register_device(&imx_wdt_device0, NULL);
 }