thunderbolt: Add support for PCIe tunneling disabled (SL5)

commit 3cd542e6

 upstream.

Recent Intel Thunderbolt firmware connection manager has support for
another security level, SL5, that disables PCIe tunneling. This option
can be turned on from the BIOS.

When this is set the driver exposes a new security level "nopcie" to the
userspace and hides the authorized attribute under connected devices.

While there we also hide it when "dponly" security level is enabled
since it is not really usable in that case anyway.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Yehezkel Bernat <YehezkelShB@gmail.com>
Signed-off-by: Liwei Song <liwei.song@windriver.com>