usb: typec: ucsi: Support for DisplayPort alt mode

This makes it possible to bind a driver to a DisplayPort
alt mode adapter devices.

The driver attempts to cope with the limitations of UCSI by
"emulating" behaviour and attempting to guess things when
ever possible in order to satisfy the requirements the
standard DisplayPort alt mode driver has.

Tested-by: Ajay Gupta <ajayg@nvidia.com>
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>