DMA-API: usb: use dma_set_coherent_mask()

The correct way for a driver to specify the coherent DMA mask is
not to directly access the field in the struct device, but to use
dma_set_coherent_mask().  Only arch and bus code should access this
member directly.

Convert all direct write accesses to using the correct API.

Acked-by: Felipe Balbi <balbi@ti.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/drivers/usb/host/ehci-platform.c b/drivers/usb/host/ehci-platform.c
index f6b790c..5b0cd2d 100644
--- a/drivers/usb/host/ehci-platform.c
+++ b/drivers/usb/host/ehci-platform.c
@@ -78,7 +78,7 @@
 	struct resource *res_mem;
 	struct usb_ehci_pdata *pdata;
 	int irq;
-	int err = -ENOMEM;
+	int err;
 
 	if (usb_disabled())
 		return -ENODEV;
@@ -91,8 +91,9 @@
 		dev->dev.platform_data = &ehci_platform_defaults;
 	if (!dev->dev.dma_mask)
 		dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
-	if (!dev->dev.coherent_dma_mask)
-		dev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
+	err = dma_set_coherent_mask(&dev->dev, DMA_BIT_MASK(32));
+	if (err)
+		return err;
 
 	pdata = dev_get_platdata(&dev->dev);