wifi: cfg80211: use strscpy to replace strlcpy

The strlcpy should not be used because it doesn't limit the source
length. Preferred is strscpy.

Signed-off-by: XueBing Chen <chenxuebing@jari.cn>
Link: https://lore.kernel.org/r/2d2fcbf7.e33.181eda8e70e.Coremail.chenxuebing@jari.cn


Signed-off-by: Johannes Berg <johannes.berg@intel.com>