thunderbolt: Introduce tb_switch_is_ice_lake()

commit 8c3b15a6 upstream.

This is needed to differentiate Ice Lake from other controllers.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Liwei Song <liwei.song@windriver.com>