thunderbolt: Fix debug log when DisplayPort adapter not available for pairing

Fix debug log when looking for a DisplayPort adapter pair of DP IN and
DP OUT. In case of no DP adapter available, log the type of the DP
adapter that is not available.

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