iwlwifi: debugfs: remove useless double condition

There's no point spelling out the same condition twice,
so remove the second one.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20220204122220.321a7e67209b.Iafb75006eab971ca6982d6efd76347d3f47bd023@changeidSigned-off-by: Luca Coelho <luciano.coelho@intel.com>

drivers/net/wireless/intel/iwlwifi/mvm/debugfs.c

@@ -425,8 +425,7 @@ static ssize_t iwl_dbgfs_amsdu_len_write(struct ieee80211_sta *sta,
 		return -EINVAL;
 
 	/* only change from debug set <-> debug unset */
-	if ((amsdu_len && mvmsta->orig_amsdu_len) ||
-	    (!!amsdu_len && mvmsta->orig_amsdu_len))
+	if (amsdu_len && mvmsta->orig_amsdu_len)
 		return -EBUSY;
 
 	if (amsdu_len) {