brcmsmac: don't start device when RfKill is engaged

This patch fixes a bug when device is being started
while RfKill switch is engaged, leading to hang
due to partial initialization of hardware.

Tested-by: <dragonn@op.pl>
Reviewed-by: NArend van Spriel <arend@broadcom.com>
Reviewed-by: NHante Meuleman <meuleman@broadcom.com>
Signed-off-by: NPiotr Haber <phaber@broadcom.com>
Signed-off-by: NArend van Spriel <arend@broadcom.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/brcm80211/brcmsmac/mac80211_if.c

@@ -304,7 +304,10 @@ static int brcms_ops_start(struct ieee80211_hw *hw)
 	wl->mute_tx = true;
 
 	if (!wl->pub->up)
-		err = brcms_up(wl);
+		if (!blocked)
+			err = brcms_up(wl);
+		else
+			err = -ERFKILL;
 	else
 		err = -ENODEV;
 	spin_unlock_bh(&wl->lock);