Commit "reset: make optional functions really optional" missed to
adjust one check in reset_control_put, causing a NULL pointer
access for optional resets.
Fixes: bb475230b8e5 "reset: make optional functions really optional" Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>