net/mlx5: HWS, don't destroy more bwc queue locks than allocated

hws_send_queues_bwc_locks_destroy destroyed more queue locks than
allocated, leading to memory corruption (occasionally) and warnings such
as DEBUG_LOCKS_WARN_ON(mutex_is_locked(lock)) in __mutex_destroy because
sometimes, the 'mutex' being destroyed was random memory.
The severity of this problem is proportional to the number of queues
configured because the code overreaches beyond the end of the
bwc_send_queue_locks array by 2x its length.

Fix that by using the correct number of bwc queues.

Fixes: 2ca62599 ("net/mlx5: HWS, added send engine and context handling")
Signed-off-by: Cosmin Ratiu <cratiu@nvidia.com>
Signed-off-by: Yevgeny Kliteynik <kliteyn@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>