thunderbolt: Add support for USB4 DROM

USB4 router DROM differs sligthly from Thunderbolt 1-3 DROM. For
instance it does not include UID and CRC8 in the header section, and it
has product descriptor genereric entry to describe the product IDs and
related information. If the "Version" field in the DROM header section
reads 3 it means the router only has USB4 DROM and if it reads 1 it
means the router supports TBT3 compatible DROM.

For this reason, update the DROM parsing code to support "pure" USB4
DROMs too.

While there drop the extra empty line at the end of tb_drom_read().

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