watchdog: f71808e_wdt: fix inaccurate report in WDIOC_GETTIMEOUT

The fintek watchdog timer can configure timeouts of second granularity
only up to 255 seconds. Beyond that, the timeout needs to be configured
with minute granularity. WDIOC_GETTIMEOUT should report the actual
timeout configured, not just echo back the timeout configured by the
user. Do so.

Fixes: 96cb4eb0

 ("watchdog: f71808e_wdt: new watchdog driver for Fintek F71808E and F71882FG")
Suggested-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Link: https://lore.kernel.org/r/5e17960fe8cc0e3cb2ba53de4730b75d9a0f33d5.1628525954.git-series.a.fatoum@pengutronix.de
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>