iwlwifi: clear iwl_cmd_meta structure before use

Resolve an issue in which out-dated fields in iwl_cmd_meta
could be used for later hardware commands.
Signed-off-by: Daniel C Halperin <daniel.c.halperin@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/iwlwifi/iwl-tx.c

@@ -970,6 +970,7 @@ int iwl_enqueue_hcmd(struct iwl_priv *priv, struct iwl_host_cmd *cmd)
 	out_cmd = txq->cmd[idx];
 	out_meta = &txq->meta[idx];
 
+	memset(out_meta, 0, sizeof(*out_meta));	/* re-initialize to NULL */
 	out_meta->flags = cmd->flags;
 	if (cmd->flags & CMD_WANT_SKB)
 		out_meta->source = cmd;