ath9k: wake up the hardware from full sleep when idle is turned off

The hardware needs a reset to recover from full sleep. Issue this reset
directly in the ath9k_config call that turns off idle, otherwise tx
remains dead until the first channel change after the idle state change

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