power: supply: max17042_battery: fix typo in MAX17042_IAvg_empty

Datasheet gives the name IAvg_empty, not LAvg_empty.

Signed-off-by: Henrik Grimler <henrik@grimler.se>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>