nl80211: Exclude PMK when sending NL80211_CMD_DEL_PMKSA explicitly
Add a check in nl80211 driver layer to not include PMK while sending
NL80211_CMD_DEL_PMKSA explicitly. Though it is taken care already in
supplicant layer by setting the pmk_len to zero, it would be good
to have a check in nl80211 layer in order to avoid future accidental
inclusions of keying material in commands that do not need them.