ath10k: extend the max_scan time

It was observed few times, the artificial max_scan limit we
are using mainly to detect FW hangs, can be not enough for
instance while being associated and during heavy traffic.

What we do if the FW won't return with scan results within
the max_time time is a scan abort.

This is especially visible with 10.X fw which in combination
with dual band HW (scanning 32 channels) can end up with
hw_scan close to 10 seconds.
Signed-off-by: Bartosz Markowski <bartosz.markowski@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>

drivers/net/wireless/ath/ath10k/wmi.c

@@ -2522,7 +2522,7 @@ void ath10k_wmi_start_scan_init(struct ath10k *ar,
 	arg->repeat_probe_time = 0;
 	arg->probe_spacing_time = 0;
 	arg->idle_time = 0;
-	arg->max_scan_time = 5000;
+	arg->max_scan_time = 20000;
 	arg->probe_delay = 5;
 	arg->notify_scan_events = WMI_SCAN_EVENT_STARTED
 		| WMI_SCAN_EVENT_COMPLETED