power: qpnp-qg: Add support for step-charging in TTF

Add TTF support for step charging by reading the parameters
from the battery profile and notifying the parameters when TTF
algorithm queries for the mode.

Change-Id: If4691f94a7085ae311643b5cbc042b14625eeda6
Signed-off-by: Anirudh Ghayal <aghayal@codeaurora.org>