usb: pd: Use new power_supply properties for PD current

Switch to setting the POWER_SUPPLY_PROP_PD_CURRENT_MAX for
indicating the current limit to the charger driver when
an explicit contract is established. Also set the
POWER_SUPPLY_PROP_PD_USB_SUSPEND_SUPPORTED property whenever
encountering the "USB Suspend Supported" bit in the first
PDO of a Source Capabilities message. This is an indication
to the charger that when the USB bus enters suspend state that
it should follow suspend rules according to USB 2.0/3.1 spec.

Change-Id: I665ec788a770632b4849b9beff8444d00e956ce1
Signed-off-by: Jack Pham <jackp@codeaurora.org>