mac80211: remove unnecessary null test before debugfs_remove()

The debugfs_remove() function can safely take NULL parameters
so the additionally null test isn't required, and there's no
other reason to have it here, so remove it.
Signed-off-by: Fabian Frederick <fabf@skynet.be>
[rewrite commit message, re-introduce blank line after assert]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/debugfs_key.c

@@ -300,10 +300,8 @@ void ieee80211_debugfs_key_update_default(struct ieee80211_sub_if_data *sdata)
 
 	lockdep_assert_held(&sdata->local->key_mtx);
 
-	if (sdata->debugfs.default_unicast_key) {
-		debugfs_remove(sdata->debugfs.default_unicast_key);
-		sdata->debugfs.default_unicast_key = NULL;
-	}
+	debugfs_remove(sdata->debugfs.default_unicast_key);
+	sdata->debugfs.default_unicast_key = NULL;
 
 	if (sdata->default_unicast_key) {
 		key = key_mtx_dereference(sdata->local,
@@ -314,10 +312,8 @@ void ieee80211_debugfs_key_update_default(struct ieee80211_sub_if_data *sdata)
 					       sdata->vif.debugfs_dir, buf);
 	}
 
-	if (sdata->debugfs.default_multicast_key) {
-		debugfs_remove(sdata->debugfs.default_multicast_key);
-		sdata->debugfs.default_multicast_key = NULL;
-	}
+	debugfs_remove(sdata->debugfs.default_multicast_key);
+	sdata->debugfs.default_multicast_key = NULL;
 
 	if (sdata->default_multicast_key) {
 		key = key_mtx_dereference(sdata->local,