wifi: iwlwifi: mvm: always free dup_data

There are some assertions in the STA removal code that can
fail, and in that case we may leak memory since we skip
the freeing.

Fix this by freeing the dup_data earlier in the function,
we already have a check for when we free the station, and
this we don't need to do it with and without MLD API, so
it's a win all around.

Fixes: a571f5f6

 ("iwlwifi: mvm: add duplicate packet detection per rx queue")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230514120631.173938681d72.Iff4b55fc52943825d6e3e28d78a24b155ea5cd22@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>