ath9k: remove a redundant call to pcipowersave

during suspend/resume ath9k_stop will always call ath_radio_disable
which will inturn call ath9k_hw_configpcipowersave, so no need to call
it explicitly in ath9k_stop

Signed-off-by: Mohammed Shafi Shajakhan <mshajakhan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>