power: supply: core: fix application of sizeof to pointer

The coccinelle check report:
./drivers/power/supply/cw2015_battery.c:692:12-18: ERROR: application of
sizeof to pointer

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Fixes: 25fd3303

 ("power: supply_core: Pass pointer to battery info")
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>