OMAP: DSS2: HDMI: fix hdmi clock name

The HDMI clock (hdmi_clk) is missing in the current OMAP4 HWMOD
database. Fix this in the DSS driver by using the old clock name
(dss_48mhz_clk).

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
diff --git a/drivers/video/omap2/dss/hdmi.c b/drivers/video/omap2/dss/hdmi.c
index 635cc00..256f27a 100644
--- a/drivers/video/omap2/dss/hdmi.c
+++ b/drivers/video/omap2/dss/hdmi.c
@@ -1698,9 +1698,9 @@
 
 	hdmi.sys_clk = clk;
 
-	clk = clk_get(&pdev->dev, "fck");
+	clk = clk_get(&pdev->dev, "dss_48mhz_clk");
 	if (IS_ERR(clk)) {
-		DSSERR("can't get fck\n");
+		DSSERR("can't get hdmi_clk\n");
 		clk_put(hdmi.sys_clk);
 		return PTR_ERR(clk);
 	}