fsl-viu: adjust for OF based clock lookup

after device tree based clock lookup became available, the VIU driver
need no longer use the previous global "viu_clk" name, but should use
the "ipg" clock name specific to the OF node

Cc: Mauro Carvalho Chehab <m.chehab@samsung.com>
Cc: linux-media@vger.kernel.org
Signed-off-by: Gerhard Sittig <gsi@denx.de>
Signed-off-by: Anatolij Gustschin <agust@denx.de>

drivers/media/platform/fsl-viu.c

@@ -1580,7 +1580,7 @@ static int viu_of_probe(struct platform_device *op)
 	}
 
 	/* enable VIU clock */
-	clk = devm_clk_get(&op->dev, "viu_clk");
+	clk = devm_clk_get(&op->dev, "ipg");
 	if (IS_ERR(clk)) {
 		dev_err(&op->dev, "failed to lookup the clock!\n");
 		ret = PTR_ERR(clk);