USB: dwc3: msm: Add support for Userspace charger detection

The userspace charger detection takes place when a standard dedicated
charger is connected.  We handover the detection part to userspace
after detecting the dedicated charger.  Create a character device
called /dev/usb_ext_chg to expose hardware register access and a
mechanism to vote against low power mode.  Add POWER_SUPPLY_PROP_TYPE
property to power_supply_property array to send charger type information
in power supply uevent.

Change-Id: Iff6a7b7e7d0cccaef3f77d0cdc10fff5b9f1732c
Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>