ath5k: fix a crash when setting coverage class before the first channel change (#9586)

SVN-Revision: 27352

package/mac80211/patches/443-ath5k_initialize_clockrate.patch

+--- a/drivers/net/wireless/ath/ath5k/base.c
++++ b/drivers/net/wireless/ath/ath5k/base.c
+@@ -2422,6 +2422,7 @@ ath5k_init_softc(struct ath5k_softc *sc,
+ 	common->ah = sc->ah;
+ 	common->hw = hw;
+ 	common->priv = sc;
++	common->clockrate = 40;
+ 
+ 	/*
+ 	 * Cache line size is used to size and align various