Commit 
d8ca16db6bb2 ("mac80211: add length check in
ieee80211_is_robust_mgmt_frame()") changed that API to take an skb,
and added "_ieee80211_is_robust_mgmt_frame" as a direct replacement
for the older API.  This is the same fix that was applied to the other
rtlwifi drivers in that commit.
Cc: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
                                return false;
                }
 
-               if ((ieee80211_is_robust_mgmt_frame(hdr)) &&
+               if ((_ieee80211_is_robust_mgmt_frame(hdr)) &&
                        (ieee80211_has_protected(hdr->frame_control)))
                        rx_status->flag &= ~RX_FLAG_DECRYPTED;
                else