power: supply: smb1398: Add support to make SMB1398 driver GKI compliant

Add support for charge pump master and slave power supplies through IIO
devices and properties under them through IIO channels under the device.

Change-Id: Iccd70399bb1326548b2aa597ec04d648ebd28097
Signed-off-by: Jishnu Prakash <jprakash@codeaurora.org>
Signed-off-by: Ashish Chavan <ashichav@codeaurora.org>