qpnp-fg-gen3: improve SOC masking algorithm

After charge termination, charging status might not get updated
until the recharge begins. This makes charge_full_update to be
not called at all thereby causing SOC masking algorithm to not
clear the charge_full flag. Use delta battery SOC interrupt to
help with this. Keep it disabled by default and enable it after
the charge termination. Disable it again when the user removes
the charger.

Since this needs delta battery SOC threshold to be configured,
add support for it.

Change-Id: Ic1a9f8a065c87efe88e315f2b2e1e1378151531b
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>