thunderbolt: Convert rest of the driver files to use SPDX identifier

This gets rid of the licence boilerplate duplicated in each file. While
there fix doubled space in domain.c author line.

No functional changes intended.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Yehezkel Bernat <yehezkelshb@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>