ath10k: fix scan abort when duration is set for hw scan

When request scan with duration 120ms on channel 1, it failed with
scan abort easily. Because scan_timeout is set to 130ms for the scan
in ath10k_hw_scan(), and timed out before scan complete, so lead
scan abort.

failed log of ath10k:
2021-04-14T14:43:29.936058Z DEBUG kernel: [67384.594846] ath10k_sdio mmc1:0001:1: wmi tlv start scan
2021-04-14T14:43:29.937896Z DEBUG kernel: [67384.595820] ath10k_sdio mmc1:0001:1: scan event started type 1 reason 7 freq 2437 req_id 40961 scan_id 40960 vdev_id 0 state starting (1)
2021-04-14T14:43:29.938357Z DEBUG kernel: [67384.596761] ath10k_sdio mmc1:0001:1: scan event bss channel type 4 reason 7 freq 2437 req_id 40961 scan_id 40960 vdev_id 0 state running (2)
2021-04-14T14:43:29.992497Z DEBUG kernel: [67384.651013] ath10k_sdio mmc1:0001:1: scan event foreign channel type 8 reason 7 freq 2412 req_id 40961 scan_id 40960 vdev_id 0 state running (2)
2021-04-14T14:43:30.063530Z DEBUG kernel: [67384.722139] ath10k_sdio mmc1:0001:1: wmi tlv stop scan
2021-04-14T14:43:30.066592Z DEBUG kernel: [67384.724403] ath10k_sdio mmc1:0001:1: scan event completed [cancelled] type 2 reason 1 freq 2412 req_id 40961 scan_id 40960 vdev_id 0 state aborting (3)

failed log of wpa_supplicant:
2021-04-14T14:43:29.981842Z DEBUG wpa_supplicant[887]: wlan0: nl80211: scan request
2021-04-14T14:43:29.981988Z DEBUG wpa_supplicant[887]: nl80211: Passive scan requested
2021-04-14T14:43:29.982202Z DEBUG wpa_supplicant[887]: nl80211: Add NL80211_SCAN_FLAG_FLUSH
2021-04-14T14:43:29.982339Z DEBUG wpa_supplicant[887]: Scan requested (ret=0) - scan timeout 30 seconds
2021-04-14T14:43:29.982491Z DEBUG wpa_supplicant[887]: nl80211: Drv Event 33 (NL80211_CMD_TRIGGER_SCAN) received for wlan0
2021-04-14T14:43:29.982629Z DEBUG wpa_supplicant[887]: wlan0: nl80211: Scan trigger
2021-04-14T14:43:29.982779Z DEBUG wpa_supplicant[887]: wlan0: Event SCAN_STARTED (47) received
2021-04-14T14:43:29.982920Z DEBUG wpa_supplicant[887]: wlan0: Own scan request started a scan in 0.000175 seconds
2021-04-14T14:43:30.082401Z DEBUG wpa_supplicant[887]: nl80211: Drv Event 35 (NL80211_CMD_SCAN_ABORTED) received for wlan0
2021-04-14T14:43:30.082704Z DEBUG wpa_supplicant[887]: wlan0: nl80211: Scan aborted
2021-04-14T14:43:30.082905Z DEBUG wpa_supplicant[887]: nl80211: Scan included frequencies: 2412
2021-04-14T14:43:30.083123Z DEBUG wpa_supplicant[887]: wlan0: Event SCAN_RESULTS (3) received
2021-04-14T14:43:30.083310Z DEBUG wpa_supplicant[887]: wlan0: Scan completed in 0.128655 seconds

This is to increase the scan_timeout with 200ms for this situation,
then scan will not timed out for this situation.

Tested-on: QCA6174 hw3.2 SDIO WLAN.RMH.4.4.1-00049
Signed-off-by: Wen Gong <quic_wgong@quicinc.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/20211026025902.26621-1-quic_wgong@quicinc.com

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

@@ -6380,13 +6380,14 @@ static int ath10k_hw_scan(struct ieee80211_hw *hw,
 		scan_timeout = min_t(u32, arg.max_rest_time *
 				(arg.n_channels - 1) + (req->duration +
 				ATH10K_SCAN_CHANNEL_SWITCH_WMI_EVT_OVERHEAD) *
-				arg.n_channels, arg.max_scan_time + 200);
-
+				arg.n_channels, arg.max_scan_time);
 	} else {
-		/* Add a 200ms margin to account for event/command processing */
-		scan_timeout = arg.max_scan_time + 200;
+		scan_timeout = arg.max_scan_time;
 	}
 
+	/* Add a 200ms margin to account for event/command processing */
+	scan_timeout += 200;
+
 	ret = ath10k_start_scan(ar, &arg);
 	if (ret) {
 		ath10k_warn(ar, "failed to start hw scan: %d\n", ret);