watchdog: imx: Add DM support

Add DM and DT probing support to iMX watchdog driver. This should
allow boards to move over to this driver, enable SYSRESET_WATCHDOG
to handle cpu_reset() if required.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Peng Fan <Peng.Fan@freescale.com>
Cc: Stefano Babic <sbabic@denx.de>
Tested-by: Heiko Schocher <hs@denx.de>
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index de9bd87..ccda432 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -28,7 +28,7 @@
 
 config IMX_WATCHDOG
 	bool "Enable Watchdog Timer support for IMX and LSCH2 of NXP"
-	select HW_WATCHDOG
+	select HW_WATCHDOG if !WDT
 	help
 	   Select this to enable the IMX and LSCH2 of Layerscape watchdog
 	   driver.