ath10k-ct: update to version 2020-04-29

ath10k-ct: update to version 2020-04-29

Pulls in workaround for TX rate code firmware bug which might as well
help track it down via different printk()s and thus possibly provide
more clue for proper fix.

Firmware currently sends wrong (0xff) TX rate code which causes
WARN_ONCE, so the workaround just changes this bogus value (0xff) into 0.

For 5.4 it also pulls in tx-queue-wake throttling patch "ath10k: Restart
xmit queues below low-water mark", which should improve performance with
high number of concurrent TCP streams.

Ref: https://github.com/greearb/ath10k-ct/pull/129
Signed-off-by: Petr Štetiar <ynezz@true.cz>