usb: pd: convert to using Type-C class

The dual_role_usb class is deprecated and no longer carried on this
kernel. Switch PD policy engine to implement an instance of the USB
Type-C class instead as it offers equivalent functionality and more.
A port partner is registered/unregistered on each attach/detach.
Userspace clients will need to be updated to handle this switch.

Change-Id: I7a6592431a95b7b44b2c118d4876a7cf06b3cb5b
Signed-off-by: Jack Pham <jackp@codeaurora.org>