staging: wfx: fix coherency of hif_scan() prototype

The function hif_scan() return the timeout for the completion of the
scan request. It is the only function from hif_tx.c that return another
thing than just an error code. This behavior is not coherent with the
rest of file. Worse, if value returned is positive, the caller can't
make say if it is a timeout or the value returned by the hardware.

Uniformize API with other HIF functions, only return the error code and
pass timeout with parameters.

Signed-off-by: Jérôme Pouiller <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/staging/wfx/hif_tx.c

···
 }
 
 int hif_scan(struct wfx_vif *wvif, struct cfg80211_scan_request *req,
-	     int chan_start_idx, int chan_num)
+	     int chan_start_idx, int chan_num, int *timeout)
 {
 	int ret, i;
 	struct hif_msg *hif;
···
 	tmo_chan_fg = 512 * USEC_PER_TU + body->probe_delay;
 	tmo_chan_fg *= body->num_of_probe_requests;
 	tmo = chan_num * max(tmo_chan_bg, tmo_chan_fg) + 512 * USEC_PER_TU;
+	if (timeout)
+		*timeout = usecs_to_jiffies(tmo);
 
 	wfx_fill_header(hif, wvif->id, HIF_REQ_ID_START_SCAN, buf_len);
 	ret = wfx_cmd_send(wvif->wdev, hif, NULL, 0, false);
 	kfree(hif);
-	return ret ? ret : usecs_to_jiffies(tmo);
+	return ret;
 }
 
 int hif_stop_scan(struct wfx_vif *wvif)

drivers/staging/wfx/hif_tx.h

···
 int hif_write_mib(struct wfx_dev *wdev, int vif_id, u16 mib_id,
 		  void *buf, size_t buf_size);
 int hif_scan(struct wfx_vif *wvif, struct cfg80211_scan_request *req80211,
-	     int chan_start, int chan_num);
+	     int chan_start, int chan_num, int *timeout);
 int hif_stop_scan(struct wfx_vif *wvif);
 int hif_join(struct wfx_vif *wvif, const struct ieee80211_bss_conf *conf,
 	     struct ieee80211_channel *channel, const u8 *ssid, int ssidlen);

drivers/staging/wfx/scan.c

···
 	wfx_tx_lock_flush(wvif->wdev);
 	wvif->scan_abort = false;
 	reinit_completion(&wvif->scan_complete);
-	timeout = hif_scan(wvif, req, start_idx, i - start_idx);
-	if (timeout < 0) {
+	ret = hif_scan(wvif, req, start_idx, i - start_idx, &timeout);
+	if (ret) {
 		wfx_tx_unlock(wvif->wdev);
-		return timeout;
+		return -EIO;
 	}
 	ret = wait_for_completion_timeout(&wvif->scan_complete, timeout);
 	if (req->channels[start_idx]->max_power != wvif->vif->bss_conf.txpower)