drm/omap: move display, dss-of, output to omapdss-base

This patch moves the common parts of omapdss to omapdss-base so that
both the current omapdss driver and the new omapdss6 driver can use
them.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
diff --git a/drivers/gpu/drm/omapdrm/dss/omapdss.h b/drivers/gpu/drm/omapdrm/dss/omapdss.h
index b644b12..dab367a 100644
--- a/drivers/gpu/drm/omapdrm/dss/omapdss.h
+++ b/drivers/gpu/drm/omapdrm/dss/omapdss.h
@@ -846,6 +846,9 @@ omapdss_of_find_source_for_first_ep(struct device_node *node);
 
 void omapdss_set_is_initialized(bool set);
 
+struct device_node *dss_of_port_get_parent_device(struct device_node *port);
+u32 dss_of_port_get_port_number(struct device_node *port);
+
 u32 dispc_read_irqstatus(void);
 void dispc_clear_irqstatus(u32 mask);
 u32 dispc_read_irqenable(void);