ath5k: added cfg80211 based rfkill support

This patch introduces initial rfkill support for the ath5k driver
based on rfkill support in the cfg80211 framework.
All rfkill related code is separated into newly created rfkill.c.

Changes to existing code are minimal:

* added a new data structure ath5k_rfkill to the ath5k_softc structure
* inserted calls to HW rfkill init/deinit routines
* ath5k_intr() has been extended to handle AR5K_INT_GPIO interrupts

Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath5k/ath5k.h

@@ -1256,6 +1256,15 @@ extern u32 ath5k_hw_get_gpio(struct ath5k_hw *ah, u32 gpio);
 extern int ath5k_hw_set_gpio(struct ath5k_hw *ah, u32 gpio, u32 val);
 extern void ath5k_hw_set_gpio_intr(struct ath5k_hw *ah, unsigned int gpio, u32 interrupt_level);
 
+/* rfkill Functions */
+#ifdef CONFIG_ATH5K_RFKILL
+extern void ath5k_rfkill_hw_start(struct ath5k_hw *ah);
+extern void ath5k_rfkill_hw_stop(struct ath5k_hw *ah);
+#else
+static inline void ath5k_rfkill_hw_start(struct ath5k_hw *ah) {}
+static inline void ath5k_rfkill_hw_stop(struct ath5k_hw *ah) {}
+#endif
+
 /* Misc functions */
 int ath5k_hw_set_capabilities(struct ath5k_hw *ah);
 extern int ath5k_hw_get_capability(struct ath5k_hw *ah, enum ath5k_capability_type cap_type, u32 capability, u32 *result);