Store ichg-max and vreg-max in bq24190_dev_info once from
bq24190_get_config() and drop the bq24190_charger_get_current_max() and
bq24190_charger_get_voltage_max() helpers.

This is a preparation patch for honoring the
constant_charge_current_max_ua and constant_charge_voltage_max_uv
values from power_supply_get_battery_info().
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>