watchdog: imx7ulp_wdt: init wdog when it was active

Paired with suspend, we can only init wdog again when it was active
and ping it once to avoid the watchdog timeout after it resumed.

Signed-off-by: Jason Liu <jason.hui.liu@nxp.com>
Signed-off-by: Alice Guo <alice.guo@nxp.com>
Reviewed-by: Ye Li <ye.li@nxp.com>
Reviewed-by: Jacky Bai <ping.bai@nxp.com>
Tested-by: Jacky Bai <ping.bai@nxp.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20220825083256.14565-7-alice.guo@oss.nxp.com


Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>