OMAP: DSS2: HDMI: change regn definition

regn divider is currently programmed to the registers without change,
but when calculating clock frequencies it is used as regn+1.

To make this similar to how DSI handles the dividers this patch changes
the regn value to be used as such for calculations, but the value
programmed to registers is regn-1.

This simplifies the clock frequency calculations, makes it similar to
DSI, and also allows us to use regn value 0 as undefined.

Cc: Mythri P K <mythripk@ti.com>
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 52731b5..4752137 100644
--- a/drivers/video/omap2/dss/hdmi.c
+++ b/drivers/video/omap2/dss/hdmi.c
@@ -60,7 +60,7 @@
 
 #define OMAP_HDMI_TIMINGS_NB			34
 
-#define HDMI_DEFAULT_REGN 15
+#define HDMI_DEFAULT_REGN 16
 #define HDMI_DEFAULT_REGM2 1
 
 static struct {
@@ -426,7 +426,7 @@
 	else
 		pi->regn = dssdev->clocks.hdmi.regn;
 
-	refclk = clkin / (pi->regn + 1);
+	refclk = clkin / pi->regn;
 
 	/*
 	 * multiplier is pixel_clk/ref_clk
@@ -452,7 +452,7 @@
 	 * is greater than 1000MHz
 	 */
 	pi->dcofreq = phy > 1000 * 100;
-	pi->regsd = ((pi->regm * clkin / 10) / ((pi->regn + 1) * 250) + 5) / 10;
+	pi->regsd = ((pi->regm * clkin / 10) / (pi->regn * 250) + 5) / 10;
 
 	/* Set the reference clock to sysclk reference */
 	pi->refsel = HDMI_REFSEL_SYSCLK;