The API enables/disables the coincell charger. It also configures the coincell charger's voltage and register settings. The charger allows the coincell (connected to VCOIN) to charge from VBAT. Change-Id: Id3802e37d8100e6a72de9fd263e7d201a7a346d2 Signed-off-by: Anirudh Ghayal <aghayal@codeaurora.org>