staging: wfx: annotate nested gc_list vs tx queue locking

staging: wfx: annotate nested gc_list vs tx queue locking

Lockdep is complaining about recursive locking, because it can't make
a difference between locked skb_queues. Annotate nested locks and avoid
double bh_disable/enable.

[...]
insmod/815 is trying to acquire lock:
cb7d6418 (&(&list->lock)->rlock){+...}, at: wfx_tx_queues_clear+0xfc/0x198 [wfx]

but task is already holding lock:
cb7d61f4 (&(&list->lock)->rlock){+...}, at: wfx_tx_queues_clear+0xa0/0x198 [wfx]

[...]
Possible unsafe locking scenario:

      CPU0
      ----
 lock(&(&list->lock)->rlock);
 lock(&(&list->lock)->rlock);

Cc: stable@vger.kernel.org
Fixes: 9bca45f3d692 ("staging: wfx: allow to send 802.11 frames")
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Link: https://lore.kernel.org/r/5e30397af95854b4a7deea073b730c00229f42ba.1581416843.git.mirq-linux@rere.qmqm.pl
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>