libertas: convert libertas driver to use an event/cmdresp queue

This patch (co-developed by Dan Williams and Holger Schurig) uses a kfifo
object for events and a swapping buffer scheme for the command response to
preserve the zero-copy semantics of the CF driver and keep memory usage low.
The main thread should only ever touch the buffer indexed by priv->resp_idx,
while the interface code is free to write to the second buffer, then swap
priv->resp_idx under the driver spinlock.  The firmware specs only permit
one in-flight command, so there will only ever be one command response to
process at a time.

Signed-off-by: Holger Schurig <hs4233@mail.mn-solutions.de>
Signed-off-by: Dan Williams <dcbw@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/libertas/debugfs.c

@@ -824,7 +824,6 @@ struct debug_data {
 /* To debug any member of struct lbs_private, simply add one line here.
  */
 static struct debug_data items[] = {
-	{"intcounter", item_size(intcounter), item_addr(intcounter)},
 	{"psmode", item_size(psmode), item_addr(psmode)},
 	{"psstate", item_size(psstate), item_addr(psstate)},
 };