power_supply: Add properties to support PPS constant current(CC) mode

Add power supply properties to support PPS CC mode charging for dual
charge pumps with MID-VBAT configuration, these properties are set from
user space.

Change-Id: Ia2d467255818dbaaf2d87f56aae39584368772ce
Signed-off-by: Sahil Chandna <chandna@codeaurora.org>