ath10k: save/restore pci config space properly

The check was't really necessary and couldn't even
work to begin with because pci_restore_state()
restores only first 64 bytes of PCI configuration
space.

Actually the PCI subsystem takes care of this so
there's no need for explicit calls to save PCI
state in ath10k.

This is necessary for future WoWLAN support.

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