small adjustment to net/mac80211/Kconfig

"def_bool n" without prompt is pointless, this should be just "bool".
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/mac80211/Kconfig

@@ -17,7 +17,7 @@ comment "CFG80211 needs to be enabled for MAC80211"
 if MAC80211 != n
 
 config MAC80211_HAS_RC
-	def_bool n
+	bool
 
 config MAC80211_RC_PID
 	bool "PID controller based rate control algorithm" if EMBEDDED