ath9k: use iowrite32 over __raw_writel

This patch changes the ath9k_pci_owl_loader to use the
same iowrite32 memory accessor that ath9k_pci is using
to communicate with the PCI(e) chip.

This will fix endian issues that came up during testing
with loaned AVM Fritz!Box 7360 (Lantiq MIPS SoCs + AR9287).

Fixes: 5a4f2040 ("ath9k: add loader for AR92XX (and older) pci(e)")
Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/ath/ath9k/ath9k_pci_owl_loader.c

@@ -83,7 +83,7 @@ static int ath9k_pci_fixup(struct pci_dev *pdev, const u16 *cal_data,
 			val = swahb32(val);
 		}
 
-		__raw_writel(val, mem + reg);
+		iowrite32(val, mem + reg);
 		usleep_range(100, 120);
 	}