wireless: fix nl80211 vendor commands

In my previous commit to validate a policy I neglected to
actually add one to the few drivers using vendor commands,
fix that now.

Reported-by: Tony Lindgren <tony@atomide.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Fixes: 901bb989

 ("nl80211: require and validate vendor command policy")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>