power: smb1390-psy: Switch SMB1390 to power_supply framework

Currently smb1390-charger-psy driver create its own class "charge
pump" and interfaces with power_supply framework drivers using pmic
voters. However, increasing dependency of smb1390-charger-psy
driver on power supply framework drivers and vice-versa, requires
smb1390-charger-psy driver to be a part of power_supply framework
to ease algorithmic flows.

Change-Id: I9717f3a2b35e947bfdde56ffc4f723d47f996a0c
Signed-off-by: Umang Agrawal <uagrawal@codeaurora.org>