ath11k: Increase the tx completion ring size

Increase the tx completion ring size to 0x8000.Also set the
idr size to be same as the completion ring size.

This avoids backpressure on the TX Completion and
corresponding TCL Data ring during high data traffic.

Signed-off-by: Sriram R <srirrama@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/1585567006-9173-1-git-send-email-srirrama@codeaurora.org