power: qpnp-qg: Add support for fast-charge config

Add logic to allow re-configuring the FIFO length
based on charging status. This may be required
for fast-charging cases where SOC needs to be
tracked fine-grain.

Change-Id: I3e51dc34cea5c97a7f901d9981f908e35b8b0fb4
Signed-off-by: Anirudh Ghayal <aghayal@codeaurora.org>