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-omap.c b/drivers/usb/host/ehci-omap.c
index 78b01fa..d0759c5 100644
--- a/drivers/usb/host/ehci-omap.c
+++ b/drivers/usb/host/ehci-omap.c
@@ -104,7 +104,7 @@
 	struct resource	*res;
 	struct usb_hcd	*hcd;
 	void __iomem *regs;
-	int ret = -ENODEV;
+	int ret;
 	int irq;
 	int i;
 	struct omap_hcd	*omap;
@@ -146,9 +146,11 @@
 	 */
 	if (!dev->dma_mask)
 		dev->dma_mask = &dev->coherent_dma_mask;
-	if (!dev->coherent_dma_mask)
-		dev->coherent_dma_mask = DMA_BIT_MASK(32);
+	ret = dma_set_coherent_mask(dev, DMA_BIT_MASK(32));
+	if (ret)
+		return ret;
 
+	ret = -ENODEV;
 	hcd = usb_create_hcd(&ehci_omap_hc_driver, dev,
 			dev_name(dev));
 	if (!hcd) {