policy_engine: Add module parameter to start USB stack

USB 3.1 super speed compliance equipment may be detected as floating
charger by PMI as it may leave D+/D- lines floating (High speed data
lines). PD Policy engine does not start USB stack which results into
compliance failure as compliance expects USB stack to be started. Add
module parameter usb_compliance_mode to start USB stack on cable
connect (w/o depending on charger type).

Change-Id: Ieb33057a85b4bcff9c1e7c32c256663dd23f17ef
Signed-off-by: Vijayavardhan Vennapusa <vvreddy@codeaurora.org>