wifi: mac80211_hwsim: init peer measurement result

If we don't get all the values here, we might pass them to
cfg80211 uninitialized. Fix that, even if the input might
then not make much sense.

Fixes: 2af3b2a6

 ("mac80211_hwsim: add PMSR report support via virtio")
Reviewed-by: Miriam Rachel Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://msgid.link/20240418105220.e1317621c1f9.If7dd447de24d7493d133284db5e9e482e4e299f8@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>