USB: OTG: msm: Add support for proprietary charger detection

Proprietary chargers pull D+/- to specific voltages between 2.0-3.3V
(VLGC) for identification.  The DM voltage may not exceed VLGC due
to pull-down resistor.  Hence a proprietary charger is detected as
a Standard downstream port (SDP).  Read line state to distinguish
between SDP and proprietary charger.  The DP voltage would exceed
VLGC for proprietary chargers.

D- can be greater than VLGC when a low speed device is attached via
Accessory charger adapter (ACA-A). Hence mark the charger as ACA-A
if ID resistance is RID_A and D- > VLGC

CRs-Fixed: 368688
Change-Id: I3497efbe025abf150078a19d69254f75f5df5b2a
Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>