power: supply: axp288_charger: Fix wrong regmap_update_bits

To set a bit to 1 one needs to pass the mask for the bit to set
as second argument into regmap_update_bits, not "1".

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>