dwc3-msm: Remove pull downs from D+ and D- lines upon cable connect

Currently D+ and D- lines are pulled down when usb cable is not
connected. For proper USB type detection pull downs on these lines
need to be removed. Hence charger driver notifies dwc3 driver to
remove pull down by POWER_SUPPLY_PROP_REMOVE_PULLDOWN property.
Removing pulldown is achieved by turning on 3.3V analog voltage rail.
Upon disconnect same property is updated to turn off the rail.

CRs-Fixed: 797797
Change-Id: If366216d3dc25efa8302acef700624d3a5239752
Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>