lineage/interfaces: add fastcharge HAL

 * Several OEMs let the user decide whether to enable or disable quick
   charging technology when using a quickcharge charger.
   Samsung, for example, exposes a sysfs node to disable it at
   will, depending on what the user sets in battery settings UI.

 * Disabling fast charge may be useful for reducing the heat produced by
   the device while charging, or for extending the lifespan of the battery.

 * This commit introduces the fastcharge HAL to implement the possibility
   to disable fastcharge at will by the user for devices that support
   such feature.

Change-Id: I7ce6862d42e7087808fa6e1f023d6bb1f106fb0e
2 files changed