ath11k: pci: read select_window register to ensure write is finished

Just when resume from WoW, the write to select_window doesn't take
effect immediately, so read the register again to ensure the write
operation is finished.

Another change is to reset select_window to ZERO because this
register isn't restored after WoW, so the content of this register
becomes ZERO too.

Tested-on: QCA6390 hw2.0 PCI WLAN.HST.1.0.1-01740-QCAHSTSWPLZ_V2_TO_X86-1
Signed-off-by: Carl Huang <cjhuang@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/1607708150-21066-4-git-send-email-kvalo@codeaurora.org

drivers/net/wireless/ath/ath11k/pci.c

@@ -126,6 +126,7 @@ static inline void ath11k_pci_select_window(struct ath11k_pci *ab_pci, u32 offse
 	if (window != ab_pci->register_window) {
 		iowrite32(WINDOW_ENABLE_BIT | window,
 			  ab->mem + WINDOW_REG_ADDRESS);
+		ioread32(ab->mem + WINDOW_REG_ADDRESS);
 		ab_pci->register_window = window;
 	}
 }