libertas: convert CMD_802_11_RADIO_CONTROL to a direct command

and return errors for operations like join & scan that aren't possible
when the radio is turned off.

Signed-off-by: Dan Williams <dcbw@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/libertas/scan.c b/drivers/net/wireless/libertas/scan.c
index 4b27456..8f66903 100644
--- a/drivers/net/wireless/libertas/scan.c
+++ b/drivers/net/wireless/libertas/scan.c
@@ -944,6 +944,11 @@
 
 	lbs_deb_enter(LBS_DEB_WEXT);
 
+	if (!priv->radio_on) {
+		ret = -EINVAL;
+		goto out;
+	}
+
 	if (!netif_running(dev)) {
 		ret = -ENETDOWN;
 		goto out;