iwlagn: fix command queue timeout

If the command queue is constantly busy,
which can happen in P2P, the hangcheck
timer will frequently find a command in
it and will eventually reset the device
because nothing sets the timestamp for
this queue when commands are processed.

Fix this by setting the timestamp when
a command completes.

Cc: stable@kernel.org #2.6.39, #3.0.0 #3.1.0
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
SIgned-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

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

@@ -771,6 +771,8 @@ void iwl_tx_cmd_complete(struct iwl_priv *priv, struct iwl_rx_mem_buffer *rxb)
 	cmd = txq->cmd[cmd_index];
 	meta = &txq->meta[cmd_index];
 
+	txq->time_stamp = jiffies;
+
 	iwlagn_unmap_tfd(priv, meta, &txq->tfds[index], DMA_BIDIRECTIONAL);
 
 	/* Input error checking is done when commands are added to queue. */