OMAPDSS: move the creation of debugfs files

Instead of having an ugly #ifdef mess in the core.c for creating debugfs
files, add a dss_debugfs_create_file() function that the dss drivers
can use to create the debugfs files.

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 45e9841..e0ab108 100644
--- a/drivers/video/omap2/dss/hdmi.c
+++ b/drivers/video/omap2/dss/hdmi.c
@@ -420,7 +420,7 @@
 	}
 }
 
-void hdmi_dump_regs(struct seq_file *s)
+static void hdmi_dump_regs(struct seq_file *s)
 {
 	mutex_lock(&hdmi.lock);
 
@@ -810,6 +810,8 @@
 
 	hdmi_panel_init();
 
+	dss_debugfs_create_file("hdmi", hdmi_dump_regs);
+
 #if defined(CONFIG_SND_OMAP_SOC_OMAP4_HDMI) || \
 	defined(CONFIG_SND_OMAP_SOC_OMAP4_HDMI_MODULE)