This patch adds the ability for a VSI to use multiple Tx queues. More
specifically, the patch
    1) Provides the ability to update the Tx scheduler tree in the
       firmware. The driver can configure the Tx scheduler tree by
       adding/removing multiple Tx queues per TC per VSI.

    2) Allows a VSI to reconfigure its Tx queues during runtime.

    3) Synchronizes the Tx scheduler update operations using locks.
Signed-off-by: NAnirudh Venkataramanan <anirudh.venkataramanan@intel.com>
Tested-by: NTony Brelinski <tonyx.brelinski@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>