ath10k: simplify ath10k_ce_init() wake up handling

ath10k_ce_init() and the functions it calls wakeup
the chip multiple times. Simplify that to call
ath10k_pci_wake() only once. This also makes it
easier to add error handling when wakeup fails.

Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>