iwlwifi: mvm: fix inactive TID removal return value usage

The function iwl_mvm_remove_inactive_tids() returns bool, so we
should just check "if (ret)", not "if (ret >= 0)" (which would
do nothing useful here). We obviously therefore cannot use the
return value of the function for the free_queue, we need to use
the queue (i) we're currently dealing with instead.

Cc: stable@vger.kernel.org # v5.4+
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/iwlwifi.20200417100405.9d862ed72535.I9e27ccc3ee3c8855fc13682592b571581925dfbd@changeid