iwmc3200wifi: fix NULL pointer dereference in pmkid update

When handling IWM_CMD_PMKID_FLUSH command, the bssid and
pmkid in pmksa are all NULL. Check it before memcpy.
Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Acked-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/iwmc3200wifi/commands.c

@@ -970,8 +970,10 @@ int iwm_send_pmkid_update(struct iwm_priv *iwm,
 	memset(&update, 0, sizeof(struct iwm_umac_pmkid_update));
 
 	update.command = cpu_to_le32(command);
-	memcpy(&update.bssid, pmksa->bssid, ETH_ALEN);
-	memcpy(&update.pmkid, pmksa->pmkid, WLAN_PMKID_LEN);
+	if (pmksa->bssid)
+		memcpy(&update.bssid, pmksa->bssid, ETH_ALEN);
+	if (pmksa->pmkid)
+		memcpy(&update.pmkid, pmksa->pmkid, WLAN_PMKID_LEN);
 
 	ret = iwm_send_wifi_if_cmd(iwm, &update,
 				   sizeof(struct iwm_umac_pmkid_update), 0);