OMAPDSS: DISPC: Remove omap_dss_device pointer usage from dispc_mgr_pclk_rate()

The pixel clock rate for the TV manager is calculated by checking the device
type connected to the manager, and then requesting the VENC/HDMI interface for
the pixel clock rate.

Remove the use of omap_dss_device pointer from here by checking which interface
generates the pixel clock by reading the DSS_CTRL.VENC_HDMI_SWITCH bit.
Signed-off-by: Archit Taneja <archit@ti.com>

drivers/video/omap2/dss/dispc.c

@@ -2643,13 +2643,14 @@ unsigned long dispc_mgr_pclk_rate(enum omap_channel channel)
 
 		return r / pcd;
 	} else {
-		struct omap_dss_device *dssdev =
-			dispc_mgr_get_device(channel);
+		enum dss_hdmi_venc_clk_source_select source;
 
-		switch (dssdev->type) {
-		case OMAP_DISPLAY_TYPE_VENC:
+		source = dss_get_hdmi_venc_clk_source();
+
+		switch (source) {
+		case DSS_VENC_TV_CLK:
 			return venc_get_pixel_clock();
-		case OMAP_DISPLAY_TYPE_HDMI:
+		case DSS_HDMI_M_PCLK:
 			return hdmi_get_pixel_clock();
 		default:
 			BUG();