ath5k: Fix reset and interrupts for AHB type of devices.

On WiSoc we cannot access mac register before it is resetted.
It will crash hardware otherwise.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Wojciech Dubowik <Wojciech.Dubowik@neratec.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>