ath5k: fix typos, bad comment formatting and GHz in place of MHz

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

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

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

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

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

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

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

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

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

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

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

drivers/net/wireless/ath/ath5k/mac80211-ops.c

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

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

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

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

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

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