ath10k: expand the wmi mgmt queue limit to 128

It was obseverd many times the short queue limit can be
easily exceeded in case of AP multiple BSSID scenarios.

"ath10k: wmi mgmt_tx queue limit reached."

This was leading to TX packets drops.

This patch expands the queue limit to 128. After many stress
experiments (high traffic and lot of management frames in
the air) the new value seems to fix the problem on platforms
with limited resources.

Reported-By: Tomasz Skapski <tomasz.skapski@tieto.com>
Signed-off-by: Bartosz Markowski <bartosz.markowski@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>