power: qpnp-smbcharger: Add support to configure recharge threshold source

Currently, we're configuring the recharge threshold source as analog
ADC by default. In certain cases like where the system load is high
and the input current is lesser than 500mA, charger inhibit interrupt
fires frequently right after the charger insertion. Since the power
supply change notification for battery full is sent based on this
interrupt, an interrupt storm prematurely indicates battery full to
the userspace.

To avoid this, we should program the recharge threshold source as fuel
gauge.This will make the charger to be in sync with the fuel gauge and
helping in reducing spurious chg-inhibit interrupts.

CRs-Fixed: 723434
Change-Id: I784d885f80c1944bd64e779a5946227e7b18ef8d
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>