power: supply: wilco_ec: Add long life charging mode

This is a long life mode set in the factory for extended warranty
battery, the power charging rate is customized so that battery at
work last longer.

Presently switching to a different battery charging mode is through
EC PID 0x0710 to configure the battery firmware, this operation will
be blocked by EC with failure code 0x01 when PLL mode is already
in use.

Signed-off-by: Crag Wang <crag.wang@dell.com>
Reviewed-by: Mario Limonciello <mario.limonciello@dell.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

power_supply: wilco_ec: Add charging config driver

Add a driver to control the charging algorithm used on Wilco
devices. See Documentation/ABI/testing/sysfs-class-power-wilco
for the userspace interface and other info.

Signed-off-by: Nick Crews <ncrews@chromium.org>
Reviewed-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>