power: qcom: step-chg: Add notification on changing FCC

Call power supply changed to notify the clients that
the FCC value has been changed according to JEITA conditions.

CRs-Fixed: 2200348

Change-Id: I33bc5d7bd1bae6a348a5c8ba46adb1e596d3d46a
Signed-off-by: Umang Agrawal <uagrawal@codeaurora.org>