ath5k: use bool type for no_hw_rfkill_switch module parameter

Avoids this:

  CC [M]  drivers/net/wireless/ath/ath5k/base.o
drivers/net/wireless/ath/ath5k/base.c: In function ‘__check_no_hw_rfkill_switch’:
drivers/net/wireless/ath/ath5k/base.c:85:1: warning: return from incompatible pointer type
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath5k/base.c

@@ -80,7 +80,7 @@ static bool modparam_fastchanswitch;
 module_param_named(fastchanswitch, modparam_fastchanswitch, bool, S_IRUGO);
 MODULE_PARM_DESC(fastchanswitch, "Enable fast channel switching for AR2413/AR5413 radios.");
 
-static int ath5k_modparam_no_hw_rfkill_switch;
+static bool ath5k_modparam_no_hw_rfkill_switch;
 module_param_named(no_hw_rfkill_switch, ath5k_modparam_no_hw_rfkill_switch,
 								bool, S_IRUGO);
 MODULE_PARM_DESC(no_hw_rfkill_switch, "Ignore the GPIO RFKill switch state");