power: supply: axp288_charger: Use regmap_update_bits to set the input limits

Use regmap_update_bits in axp288_charger_set_vbus_inlmt, instead of DIY
code.

Reviewed-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>