brcmfmac: clear events in brcmf_fweh_detach() will always fail

Clearing firmware events in brcmf_fweh_detach() is always failing
because it is called only upon driver remove and communication
with firmware is no longer possible.

Reviewed-by: Hante Meuleman <hante.meuleman@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieter-paul.giesberts@broadcom.com>
Reviewed-by: Franky Lin <franky.lin@broadcom.com>
Signed-off-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/broadcom/brcm80211/brcmfmac/fweh.c

@@ -303,16 +303,7 @@ void brcmf_fweh_attach(struct brcmf_pub *drvr)
 void brcmf_fweh_detach(struct brcmf_pub *drvr)
 {
 	struct brcmf_fweh_info *fweh = &drvr->fweh;
-	struct brcmf_if *ifp = brcmf_get_ifp(drvr, 0);
-	s8 eventmask[BRCMF_EVENTING_MASK_LEN];
 
-	if (ifp) {
-		/* clear all events */
-		memset(eventmask, 0, BRCMF_EVENTING_MASK_LEN);
-		(void)brcmf_fil_iovar_data_set(ifp, "event_msgs",
-					       eventmask,
-					       BRCMF_EVENTING_MASK_LEN);
-	}
 	/* cancel the worker */
 	cancel_work_sync(&fweh->event_work);
 	WARN_ON(!list_empty(&fweh->event_q));