iwm(4) bssid addr fix

[Stefan Sperling]

Adrian Chadd noted that Linux iwlwifi sends the broadcast address to
the firmware when not associated, rather than zeros.

ok?

Index: if_iwm.c
===================================================================
RCS file: /cvs/src/sys/dev/pci/if_iwm.c,v
retrieving revision 1.46
diff -u -p -r1.46 if_iwm.c
--- if_iwm.c    19 Jul 2015 21:40:00 -0000      1.46
+++ if_iwm.c    22 Sep 2015 17:14:32 -0000
@@ -4718,7 +4718,7 @@ iwm_mvm_mac_ctxt_cmd_common(struct iwm_s
        if (in->in_assoc) {
                IEEE80211_ADDR_COPY(cmd->bssid_addr, ni->ni_bssid);
        } else {
-               memset(cmd->bssid_addr, 0, sizeof(cmd->bssid_addr));
+               IEEE80211_ADDR_COPY(cmd->bssid_addr, etherbroadcastaddr);
        }
        iwm_mvm_ack_rates(sc, in, &cck_ack_rates, &ofdm_ack_rates);
        cmd->cck_rates = htole32(cck_ack_rates);