watchdog: imx7ulp: Pass the wdog instance inimx7ulp_wdt_enable()

It is more natural to pass the watchdog instance inside
imx7ulp_wdt_enable() instead of the base address.

This also has the benefit to reduce the code a bit.

Signed-off-by: Fabio Estevam <festevam@gmail.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20191029174037.25381-2-festevam@gmail.com


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