ath10k: remove target soc ps code

The soc powersave was disabled by default. It
never was fully tested. Some hw apparently had
problems with it and the implementation itself had
a possible race.

Just remove the refcounting and simply wake up the
device when probing and put to sleep when
removing.

kvalo: make ath10k_pci_wake() and _sleep() static

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