mac80211: remove unnecessary key condition

When we reach this point, the key cannot be NULL. Remove the condition
that suggests otherwise.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/20190830112451.21655-6-luca@coelho.fi


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