bus: brcmstb_gisb: Honor the "big-endian" and "native-endian" DT properties

On chips strapped for BE, we'll need to use ioread32be/iowrite32be instead of
ioread32/iowrite32.
Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>

drivers/bus/brcmstb_gisb.c

@@ -91,6 +91,7 @@ static const int gisb_offsets_bcm7445[] = {
 struct brcmstb_gisb_arb_device {
 	void __iomem	*base;
 	const int	*gisb_offsets;
+	bool		big_endian;
 	struct mutex	lock;
 	struct list_head next;
 	u32 valid_mask;
@@ -108,6 +109,9 @@ static u32 gisb_read(struct brcmstb_gisb_arb_device *gdev, int reg)
 	if (offset == -1)
 		return 1;
 
+	if (gdev->big_endian)
+		return ioread32be(gdev->base + offset);
+	else
 		return ioread32(gdev->base + offset);
 }
 
@@ -117,6 +121,10 @@ static void gisb_write(struct brcmstb_gisb_arb_device *gdev, u32 val, int reg)
 
 	if (offset == -1)
 		return;
+
+	if (gdev->big_endian)
+		iowrite32be(val, gdev->base + reg);
+	else
 		iowrite32(val, gdev->base + reg);
 }
 
@@ -296,6 +304,7 @@ static int __init brcmstb_gisb_arb_probe(struct platform_device *pdev)
 		return -EINVAL;
 	}
 	gdev->gisb_offsets = of_id->data;
+	gdev->big_endian = of_device_is_big_endian(dn);
 
 	err = devm_request_irq(&pdev->dev, timeout_irq,
 				brcmstb_gisb_timeout_handler, 0, pdev->name,