wifi: nl80211: call kfree without a NULL check

wifi: nl80211: call kfree without a NULL check

Coverity is unhappy because we may leak old_radio_rts_threshold. Since
this pointer is only valid in the context of the function and kfree is
NULL pointer safe, don't check and just call kfree.
Note that somehow, we were checking old_rts_threshold to free
old_radio_rts_threshold which is a bit odd.

Fixes: 264637941cf4 ("wifi: cfg80211: Add Support to Set RTS Threshold for each Radio")
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Link: https://patch.msgid.link/20251020075745.44168-1-emmanuel.grumbach@intel.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>