gpio-charger: Use cansleep version of gpio_set_value

Context of gpio_charger_get_property is sleepable so we should
use gpio_set_value_cansleep instead of gpio_set_value.

It will remove WARN_ON incase of using gpio from i2c-to-gpio
expander like pca953x.

Signed-off-by: Pritesh Raithatha <praithatha@nvidia.com>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>