ath10k: fix ath10k_ce_init() failpath

Make sure to put target back to sleep. This was a
minor issue as it didn't really matter if we put
target back to sleep at this point. It just looked
wrong.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>