Revert "wifi: mac80211_hwsim: check the return value of nla_put_u32"

This reverts commit b970ac68 ("wifi: mac80211_hwsim: check the
return value of nla_put_u32") since it introduced a memory leak in
the error path, which seems worse than sending an incomplete skb,
and the put can't fail anyway since the SKB was just allocated.

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