UPSTREAM: mac80211_hwsim: fix memory leak on netlink TX failure

If the packet can't be delivered to userspace (at all or
quickly enough) then it can leak - fix that.

Signed-off-by: Ben Greear <greearb@candelatech.com>
[rewrite commit message]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
(cherry picked from commit b7bc9679)
Bug: 70214720
Change-Id: I8e125100ee10954273c99f5ba2359833f376f3c2
Signed-off-by: Alistair Strachan <astrachan@google.com>