watchdog: imx2_wdt: set watchdog parent device

If on watchdog device registration a parent device is not set, then
the registered watchdog is considered to be a virtual device:

  /sys/devices/virtual/watchdog/watchdog0
  /sys/devices/virtual/watchdog/watchdog1

Setting a correct reference to a platform device allows to
distinguish multiple instances of iMX2+ hardware watchdogs:

  /sys/devices/soc0/soc/2000000.aips-bus/20bc000.wdog/watchdog/watchdog0
  /sys/devices/soc0/soc/2000000.aips-bus/20c0000.wdog/watchdog/watchdog1

Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

drivers/watchdog/imx2_wdt.c

@@ -258,6 +258,7 @@ static int __init imx2_wdt_probe(struct platform_device *pdev)
 	wdog->ops		= &imx2_wdt_ops;
 	wdog->min_timeout	= 1;
 	wdog->max_timeout	= IMX2_WDT_MAX_TIME;
+	wdog->parent		= &pdev->dev;
 
 	clk_prepare_enable(wdev->clk);