wifi: mac80211_hwsim: fix warning

WARN_ON("string") will unconditionally trigger a warning, but
not really do what it may look like. Use WARN(1, ...) instead
and add the mode number as well.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Link: https://patch.msgid.link/20240705133921.a50aa5b15ece.I9a25b7448b0498c0c2e503986978dae165c8bdf8@changeid


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