brcmfmac: initialize escan function pointer during scheduled scan

For scheduled scan results the driver does a escan to obtain BSS
details from the firmware. However, the escan uses a dynamically
determined function. This needs to be set appropriately when handling
scheduled scan results to avoid NULL pointer access.
Reviewed-by: NFranky Lin <frankyl@broadcom.com>
Reviewed-by: NHante Meuleman <meuleman@broadcom.com>
Reviewed-by: NPieter-Paul Giesberts <pieterpg@broadcom.com>
Reviewed-by: NDaniel (Deognyoun) Kim <dekim@broadcom.com>
Signed-off-by: NArend van Spriel <arend@broadcom.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

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

@@ -2989,6 +2989,7 @@ brcmf_notify_sched_scan_results(struct brcmf_if *ifp,
 		}
 
 		set_bit(BRCMF_SCAN_STATUS_BUSY, &cfg->scan_status);
+		cfg->escan_info.run = brcmf_run_escan;
 		err = brcmf_do_escan(cfg, wiphy, ifp, request);
 		if (err) {
 			clear_bit(BRCMF_SCAN_STATUS_BUSY, &cfg->scan_status);