drm/omap: add dispc_ops

We want to change the dispc API from plain functions to a struct with
functions pointers, so that omapdrm can call either omapdss or omapdss6
depending on the platform.

This patch adds 'struct dispc_ops' and adds functions to omapdss-base
to set and get the ops.

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

drivers/gpu/drm/omapdrm/dss/base.c

@@ -2,6 +2,7 @@
 #include <linux/module.h>
 
 static bool dss_initialized;
+static const struct dispc_ops *ops;
 
 void omapdss_set_is_initialized(bool set)
 {
@@ -15,6 +16,18 @@ bool omapdss_is_initialized(void)
 }
 EXPORT_SYMBOL(omapdss_is_initialized);
 
+void dispc_set_ops(const struct dispc_ops *o)
+{
+	ops = o;
+}
+EXPORT_SYMBOL(dispc_set_ops);
+
+const struct dispc_ops *dispc_get_ops(void)
+{
+	return ops;
+}
+EXPORT_SYMBOL(dispc_get_ops);
+
 MODULE_AUTHOR("Tomi Valkeinen <tomi.valkeinen@ti.com>");
 MODULE_DESCRIPTION("OMAP Display Subsystem Base");
 MODULE_LICENSE("GPL v2");