Without this you will get a panic if the device initialization
fails. Also, free ath_hw instance properly. ath9k_hw_deinit()
shouldn't do it.

Cc: stable@kernel.org
Signed-off-by: NSujith <Sujith.Manoharan@atheros.com>
Signed-off-by: NLuis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>