platform/x86: ideapad: Expose charge_types

platform/x86: ideapad: Expose charge_types

Some Ideapad models support a battery conservation mode which limits the
battery charge threshold for longer battery longevity. This is currently
exposed via a custom conservation_mode attribute in sysfs.

The newly introduced charge_types sysfs attribute is a standardized
replacement for laptops with a fixed end charge threshold. Setting it to
`Long Life` would enable battery conservation mode. The standardized
user space API would allow applications such as UPower to detect laptops
which support this battery longevity mode and set it.

Tested on an Lenovo ideapad U330p.

Signed-off-by: Jelle van der Waa <jvanderwaa@redhat.com>
Suggested-By: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Reviewed-by: Armin Wolf <W_Armin@gmx.de>
Link: https://lore.kernel.org/r/20250514201054.381320-1-jvanderwaa@redhat.com
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>