ath10k: change htt tx desc/qcache peer limit config

The number of HTT Tx descriptors and qcache peer
limit aren't hw-specific. In fact they are
firmware specific and should not be placed in
hw_params.

The QCA4019 limits were submitted with the peer
flow control firmware only and to my understanding
there's no non-peer-flow-ctrl QCA4019 firmware.

However QCA99X0 is planned to run firmware
supporting the feature as well. Therefore this
patch enables QCA99X0 to use 2500 tx descriptors
whenever possible instead of just 1424.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>