power: pm8921-charger: end of charge fixes

The charger driver calls the BMS to indicate charging ended with a
full battery. If the battery is warm/cool, do tell the bms that
charging ended but don't indicate that the battery is full. The
battery is not charged up to its full potential when its warm or
cool.

Moreover, if the max voltage until which the battery will be charged
changed from the last time eoc was checked, reset the counter.
Eoc should not be declared if the vdd max keeps changing.

Also, clean up the eoc_worker() by merging the two if blocks that
check if an external charger is absent. There is no need for
those separate code blocks - one will do.

Change-Id: I27759a00c8f44333d1629773485f407fdd4d0b69
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>