iwlwifi: mvm: Set TX_CMD_FLG_PROT_REQUIRE correctly

Previously the protection flag wasn't set on multicast frames even if
the RA is unicast. Fix this by checking addr1 instead.
Signed-off-by: Andrei Otcheretianski <andrei.otcheretianski@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>

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

@@ -278,7 +278,7 @@ void iwl_mvm_set_tx_cmd(struct iwl_mvm *mvm, struct sk_buff *skb,
 	}
 
 	if (ieee80211_is_data(fc) && len > mvm->rts_threshold &&
-	    !is_multicast_ether_addr(ieee80211_get_DA(hdr)))
+	    !is_multicast_ether_addr(hdr->addr1))
 		tx_flags |= TX_CMD_FLG_PROT_REQUIRE;
 
 	if (fw_has_capa(&mvm->fw->ucode_capa,