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/dev.h b/drivers/net/wireless/libertas/dev.h
index 560d4d3..fd59e18 100644
--- a/drivers/net/wireless/libertas/dev.h
+++ b/drivers/net/wireless/libertas/dev.h
@@ -293,8 +293,7 @@
 	u16 nextSNRNF;
 	u16 numSNRNF;
 
-	u8 radioon;
-	u32 preamble;
+	u8 radio_on;
 
 	/** data rate stuff */
 	u8 cur_rate;