thunderbolt: Add DisplayPort 2.x tunneling support

This adds support for the UHBR (Ultra High Bit Rate) bandwidths
introduced with DisplayPort 2.0 (and refined in 2.1). These can go up to
80 Gbit/s and their support is represent in additional bits in the DP IN
capability.

This updates the DisplayPort tunneling to support these new rates too.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>