iw: fix ftm_request missing arguments segfault
iw: fix ftm_request missing arguments segfault

When expected argument <config-file> is not passed to arguemts iw
segfaults.

Example: iw wlp2s0 measurement ftm_request

This fixes it.

Signed-off-by: Benjamin Aschenbrenner <9b5b9136cabcf75a148c2e0de1aaa63ccdc2ae90@gmail.com>
Link: https://lore.kernel.org/r/20210410111937.32813-2-9b5b9136cabcf75a148c2e0de1aaa63ccdc2ae90@gmail.com
Signed-off-by: Johannes Berg <bff32994ff0f8d048f262a8388145a71b6071bfe@intel.com>

greearb/iw-ct,greearb/iw-ct