power: qpnp-smbcharger: introduce FCC voting

Instead of having callsites track other reasons and their values before
updating FastChargeCurrent (FCC), use the pmic-voter to do this.

Change-Id: I7c3bea5529377b8233a5c697b1a042477c2834ac
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>
Signed-off-by: Nicholas Troast <ntroast@codeaurora.org>