usb: dwc3: Add current override module params for DCP/HVDCP chargers

In case of DCP and HVDCP chargers, the current drawn is 1500mA and 1800mA
respectively. In case more current needs to be drawn, add module params
to override these values.
The DCP current can be modified as:
   echo 1600 > /sys/module/dwc3_msm/parameters/dcp_max_current
and for HVDCP it can be modified as:
   echo 2000 > /sys/module/dwc3_msm/parameters/hvdcp_max_current

Change-Id: I37f9a03c1e8f6cbeac22e56a236100c1a9b8953a
Signed-off-by: Azhar Shaikh <azhars@codeaurora.org>