iwlwifi: support host command with copied data

In addition to the NOCOPY flag, add a DUP flag that
tells the transport to kmemdup() the buffer and free
it after the command completes.

Currently this is only supported for a single buffer
in a given command, but that could be extended if it
should be needed.

Reviewed-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

drivers/net/wireless/iwlwifi/pcie/rx.c

@@ -452,6 +452,9 @@ static void iwl_rx_handle_rxbuf(struct iwl_trans *trans,
 			/* The original command isn't needed any more */
 			kfree(txq->entries[cmd_index].copy_cmd);
 			txq->entries[cmd_index].copy_cmd = NULL;
+			/* nor is the duplicated part of the command */
+			kfree(txq->entries[cmd_index].free_buf);
+			txq->entries[cmd_index].free_buf = NULL;
 		}
 
 		/*