power: smb1390: Allow taper exit if increase in float voltage

Due to reduction of float voltage in JEITA condition, taper charging
can be initiated at a lower float voltage value. On removal of JEITA
condition, float voltage scales back to its default value, but as per
current SW design, once taper charging is initiated, charge pump holds
its reduction vote on FCC until disabled. Due to this, FCC does not
scale back to its default value, restricting charge current further
down the charge cycle.

Add support to exit taper charging on increase in float voltage if it
was initiated on reduced float voltage.

Change-Id: I7468f6e70da39f00aa74cee07da0b732f7be5a02
Signed-off-by: Umang Agrawal <uagrawal@codeaurora.org>