OMAP: DSS2: HDMI: Use dss_device clock configuration for HDMI PLL parameters

Move some of the configurable HDMI PLL parameters to dssdev.clock struct.
Cleanup the function hdmi_compute_pll() by using the parameters defined in the
board file and do some cosmetic modifications.

Signed-off-by: Archit Taneja <archit@ti.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

include/video/omapdss.h

@@ -438,6 +438,11 @@ struct omap_dss_device {
 			u16 lp_clk_div;
 			enum omap_dss_clk_source dsi_fclk_src;
 		} dsi;
+
+		struct {
+			u16 regn;
+			u16 regm2;
+		} hdmi;
 	} clocks;
 
 	struct {