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/dispc.c b/drivers/video/omap2/dss/dispc.c
index 2570773..534f931 100644
--- a/drivers/video/omap2/dss/dispc.c
+++ b/drivers/video/omap2/dss/dispc.c
@@ -2761,7 +2761,7 @@
 }
 #endif
 
-void dispc_dump_regs(struct seq_file *s)
+static void dispc_dump_regs(struct seq_file *s)
 {
 	int i, j;
 	const char *mgr_names[] = {
@@ -3551,6 +3551,11 @@
 
 	dispc_runtime_put();
 
+	dss_debugfs_create_file("dispc", dispc_dump_regs);
+
+#ifdef CONFIG_OMAP2_DSS_COLLECT_IRQ_STATS
+	dss_debugfs_create_file("dispc_irq", dispc_dump_irqs);
+#endif
 	return 0;
 
 err_runtime_get: