power: smb1390-psy: Support PPS constant current(CC) mode

Add support for PPS CC mode for dual charge pumps with MID-VBAT
configuration.

If a charging adapter is put in constant current (cc) mode during charging,
the supply provides the requested constant current. As a result, the
output voltage is automatically adjusted according to the load, and falls
into charge pump operational range.

On USB insertion, if SOC is greater than the specified threshold,
disable the charge pumps.

During Taper, Disable Slave SMB1390 and Master SMB1390,
when FCC drops below their respective cutoff thresholds.

Change-Id: I2d821ff566f2059a36f9919d7b26ee5347b1820e
Signed-off-by: Sahil Chandna <chandna@codeaurora.org>