Latest ath10k CT 988X firmware (beta-18).

  *  Backport much of the 10.2 firmware features from upstream QCA driver.
     This includes ANI support, adaptive CCA, tx-hang workarounds,
     and lots of other things.
     Not all of this may be enabled at this point, and more code waits to
     be backported as time and motivation allows.

  *  Fix some rate-control issues where ath10k in station mode (at least), would
     sometimes get stuck at low rates.  This appeared to be a probe related
     state machine issue in the firmware, so I added some timeout logic to kick
     the state machine if it gets stuck.  This signicantly improves throughput
     tests with many stations.

  *  Support configuring WMI WD timeout using SET_SPECIAL API.

  *  Properly configure the rx-mask on bootup to work around problem found
     by Mr. Kazior.  This should remove the need to add the driver hack he
     posted.

  *  Allow configuring pdev failed-retry threshold.  This is how many consecutive
     tx failures the firmware will allow before resetting the wifi chip (not a full
     firmware crash).

Signed-off-by: Ben Greear <greearb@candelatech.com>