thunderbolt: Ignore port locked error in tb_port_wait_for_link_width()

Sometimes when polling for the port after target link width is changed
we get back port locked notification (because the link actually was
reset and then re-trained). Instead of bailing out we can ignore these
when polling for the width change as this is expected.

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