ARM: OMAP2+: omap_device: remove warning that clk alias already exists

When an alias for a clock already exists the warning is printed. For
every module with a main_clk defined, a clk alias for fck is added.
There are some components that have the same main_clk defined, so this
is a really normal situation.

For example the am33xx edma device has 4 components using the same main
clock. So there are three warnings in the boot log for this already
existing clock alias:
	platform 49000000.edma: alias fck already exists
	platform 49000000.edma: alias fck already exists
	platform 49000000.edma: alias fck already exists

As this is only interesting for developers, this patch changes the
message to a debug message.
Signed-off-by: NMarkus Pargmann <mpa@pengutronix.de>
Signed-off-by: NTony Lindgren <tony@atomide.com>

arch/arm/mach-omap2/omap_device.c

@@ -56,7 +56,7 @@ static void _add_clkdev(struct omap_device *od, const char *clk_alias,
 
 	r = clk_get_sys(dev_name(&od->pdev->dev), clk_alias);
 	if (!IS_ERR(r)) {
-		dev_warn(&od->pdev->dev,
+		dev_dbg(&od->pdev->dev,
 			 "alias %s already exists\n", clk_alias);
 		clk_put(r);
 		return;