watchdog: da9055: Fix invalid free of devm_ allocated data

It is not required to free devm_ allocated data. Since kref_put
needs a valid release function, da9055_wdt_release_resources()
is not deleted.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>