docs: admin-guide: thunderbolt: Replace ifconfig with ip

ifconfig is a legacy tool and no longer installed by default on many
modern distributions. Update the documentation to reference ip from
iproute2 instead.

No functional change.

Signed-off-by: Jaime Saguillo Revilla <jaime.saguillo@gmail.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

Author: jasag

Documentation/admin-guide/thunderbolt.rst

@@ -370,7 +370,7 @@ is built-in to the kernel image, there is no need to do anything.
 
 The driver will create one virtual ethernet interface per Thunderbolt
 port which are named like ``thunderbolt0`` and so on. From this point
-you can either use standard userspace tools like ``ifconfig`` to
+you can either use standard userspace tools like ``ip`` to
 configure the interface or let your GUI handle it automatically.
 
 Forcing power