brcmfmac: on sdio remove first detach bus then stop worker.

Currently the function sdio_remove will first destroy the datawork
workqueue and then detach the bus. This can create the situation
where work gets added on non-existing work queue resulting in panic.
Reviewed-by: Arend Van Spriel <arend@broadcom.com>
Reviewed-by: Franky (Zhenhui) Lin <frankyl@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Reviewed-by: Daniel (Deognyoun) Kim <dekim@broadcom.com>
Signed-off-by: Hante Meuleman <meuleman@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/dhd_sdio.c

@@ -4205,14 +4205,14 @@ void brcmf_sdio_remove(struct brcmf_sdio *bus)
 		/* De-register interrupt handler */
 		brcmf_sdiod_intr_unregister(bus->sdiodev);
 
-		cancel_work_sync(&bus->datawork);
-		if (bus->brcmf_wq)
-			destroy_workqueue(bus->brcmf_wq);
-
 		if (bus->sdiodev->bus_if->drvr) {
 			brcmf_detach(bus->sdiodev->dev);
 		}
 
+		cancel_work_sync(&bus->datawork);
+		if (bus->brcmf_wq)
+			destroy_workqueue(bus->brcmf_wq);
+
 		if (bus->ci) {
 			if (bus->sdiodev->bus_if->state == BRCMF_BUS_DOWN) {
 				sdio_claim_host(bus->sdiodev->func[1]);