watchdog: da9052: Fix invalid free of devm_ allocated data

It is not required to free devm_ allocated data. Since kref_put
needs a valid release function, da9052_wdt_release_resources()
is not deleted.

Fixes following warning.
drivers/watchdog/da9052_wdt.c:59:1-6: WARNING: invalid free of
devm_ allocated data

Signed-off-by: Tushar Behera <tushar.behera@linaro.org>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>