OMAPDSS: clean up the omapdss platform data mess

The omapdss pdata handling is a mess. This is more evident when trying
to use device tree for DSS, as we don't have platform data anymore in
that case. This patch cleans the pdata handling by:

- Remove struct omap_display_platform_data. It was used just as a
  wrapper for struct omap_dss_board_info.
- Pass the platform data only to omapdss device. The drivers for omap
  dss hwmods do not need the platform data. This should also work better
  for DT, as we can create omapdss device programmatically in generic omap
  boot code, and thus we can pass the pdata to it.
- Create dss functions for get_ctx_loss_count and dsi_enable/disable_pads
  that the dss hwmod drivers can call.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
diff --git a/arch/arm/mach-omap2/display.c b/arch/arm/mach-omap2/display.c
index 60cded4..07232fd 100644
--- a/arch/arm/mach-omap2/display.c
+++ b/arch/arm/mach-omap2/display.c
@@ -191,10 +191,24 @@
 	struct omap_hwmod *oh;
 	struct platform_device *pdev;
 	int i, oh_count;
-	struct omap_display_platform_data pdata;
 	const struct omap_dss_hwmod_data *curr_dss_hwmod;
 
-	memset(&pdata, 0, sizeof(pdata));
+	/* create omapdss device */
+
+	board_data->dsi_enable_pads = omap_dsi_enable_pads;
+	board_data->dsi_disable_pads = omap_dsi_disable_pads;
+	board_data->get_context_loss_count = omap_pm_get_dev_context_loss_count;
+	board_data->set_min_bus_tput = omap_dss_set_min_bus_tput;
+
+	omap_display_device.dev.platform_data = board_data;
+
+	r = platform_device_register(&omap_display_device);
+	if (r < 0) {
+		pr_err("Unable to register omapdss device\n");
+		return r;
+	}
+
+	/* create devices for dss hwmods */
 
 	if (cpu_is_omap24xx()) {
 		curr_dss_hwmod = omap2_dss_hwmod_data;
@@ -207,16 +221,6 @@
 		oh_count = ARRAY_SIZE(omap4_dss_hwmod_data);
 	}
 
-	if (board_data->dsi_enable_pads == NULL)
-		board_data->dsi_enable_pads = omap_dsi_enable_pads;
-	if (board_data->dsi_disable_pads == NULL)
-		board_data->dsi_disable_pads = omap_dsi_disable_pads;
-
-	pdata.board_data = board_data;
-	pdata.board_data->get_context_loss_count =
-		omap_pm_get_dev_context_loss_count;
-	pdata.board_data->set_min_bus_tput = omap_dss_set_min_bus_tput;
-
 	for (i = 0; i < oh_count; i++) {
 		oh = omap_hwmod_lookup(curr_dss_hwmod[i].oh_name);
 		if (!oh) {
@@ -226,21 +230,16 @@
 		}
 
 		pdev = omap_device_build(curr_dss_hwmod[i].dev_name,
-				curr_dss_hwmod[i].id, oh, &pdata,
-				sizeof(struct omap_display_platform_data),
+				curr_dss_hwmod[i].id, oh,
+				NULL, 0,
 				NULL, 0, 0);
 
 		if (WARN((IS_ERR(pdev)), "Could not build omap_device for %s\n",
 				curr_dss_hwmod[i].oh_name))
 			return -ENODEV;
 	}
-	omap_display_device.dev.platform_data = board_data;
 
-	r = platform_device_register(&omap_display_device);
-	if (r < 0)
-		printk(KERN_ERR "Unable to register OMAP-Display device\n");
-
-	return r;
+	return 0;
 }
 
 static void dispc_disable_outputs(void)