power: supply: ab8500_charger: Fix inconsistent IS_ERR and PTR_ERR

power: supply: ab8500_charger: Fix inconsistent IS_ERR and PTR_ERR

Fix inconsistent IS_ERR and PTR_ERR in ab8500_charger_probe().

The proper pointer to be passed as argument is di->adc_main_charger_c

This bug was detected with the help of Coccinelle.

Fixes: c35e250097f3 ("power: supply: ab8500_charger: Convert to IIO ADC")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Reviewed-by: Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>