BACKPORT: mac80211_hwsim: add concurrent channels scanning support over virtio

This fixed the crash when setting channels to 2 or more when
communicating over virtio.
Bug: 182576217

Signed-off-by: Weilun Du <wdu@google.com>
Link: https://lore.kernel.org/r/20210506180530.3418576-1-wdu@google.com


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

Change-Id: Id319bd63b757237fa8601b823001024bf067c36c
Signed-off-by: Weilun Du <wdu@google.com>
(cherry picked from commit 2ed290642538fc7394c3c835b1fdc2870e38da26)