usb: typec: Add driver for DisplayPort alternate mode

DisplayPort USB Type-C Alt Mode allows DisplayPort displays
and adapters to be attached to the USB Type-C ports on the
system.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Tested-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>