ath10k: use ath10k_do_pci_wake/sleep

This removes some remaining direct use of the wake
register which could interfere with power state
tracking of the target device. This will allow
initialization code reordering.

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