power: supply: cpcap-battery: Fix missing power_supply_put()

Fix missing power_supply_put().

Cc: Arthur Demchenkov <spinal.by@gmail.com>
Cc: Carl Philipp Klemm <philipp@uvos.xyz>
Cc: Merlijn Wajer <merlijn@wizzup.org>
Cc: Pavel Machek <pavel@ucw.cz>
Fixes: 8b0134cc ("power: supply: cpcap-battery: Fix handling of lowered charger voltage")
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>