brcmfmac: reduce log level for invalid scheduled scan request

When a regular scan does not return any networks user-space does
request a scheduled scan without any matchset or ssid. This can
not be handled by the firmware so we return -EINVAL. However, as
this request is done let us not add an error message to the log.
Reviewed-by: Hante Meuleman <meuleman@broadcom.com>
Reviewed-by: Daniel (Deognyoun) Kim <dekim@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/brcm80211/brcmfmac/wl_cfg80211.c

@@ -3178,7 +3178,7 @@ brcmf_cfg80211_sched_scan_start(struct wiphy *wiphy,
 	}
 
 	if (!request->n_ssids || !request->n_match_sets) {
-		brcmf_err("Invalid sched scan req!! n_ssids:%d\n",
+		brcmf_dbg(SCAN, "Invalid sched scan req!! n_ssids:%d\n",
 			  request->n_ssids);
 		return -EINVAL;
 	}