Staging: vt6655: Fix do not use C99 // comments

Fix checkpatch.pl issues with do not use C99 //
comments in key.h
Signed-off-by: Yeliz Taneroglu <yeliztaneroglu@gmail.com>
Reviewed-by: Daniel Baluta <daniel.baluta@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/vt6655/key.h

@@ -66,4 +66,4 @@ int vnt_key_init_table(struct vnt_private *);
 int vnt_set_keys(struct ieee80211_hw *hw, struct ieee80211_sta *sta,
 		 struct ieee80211_vif *vif, struct ieee80211_key_conf *key);
 
-#endif // __KEY_H__
+#endif /* __KEY_H__ */