[bug 667] Fix the notorious "No space for Tx" bug.

We send SYSTEM_CONFIG command after the TGI_KEY command if hardware
encryption is enabled. It sometimes causes a firmware stall (firmware
doesn't respond to any request) and finally bungs up the Tx send queue.
The solution is to send SYSTEM_CONFIG command in the post association
stage from a workqueue.

Signed-off-by: James Ketrenos <jketreno@linux.intel.com>

drivers/net/wireless/ipw2200.h

@@ -1205,6 +1205,7 @@ struct ipw_priv {
 	struct work_struct adhoc_check;
 	struct work_struct associate;
 	struct work_struct disassociate;
+	struct work_struct system_config;
 	struct work_struct rx_replenish;
 	struct work_struct request_scan;
 	struct work_struct adapter_restart;