OMAPDSS: VRFB: add omap_vrfb_supported()

Add an exported function omap_vrfb_supported() which returns true if the
vrfb driver has been loaded succesfully. This can be used to decide if
VRFB can be used or not.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
diff --git a/include/video/omapvrfb.h b/include/video/omapvrfb.h
index 3792bde..bb0bd89 100644
--- a/include/video/omapvrfb.h
+++ b/include/video/omapvrfb.h
@@ -36,6 +36,7 @@
 };
 
 #ifdef CONFIG_OMAP2_VRFB
+extern bool omap_vrfb_supported(void);
 extern int omap_vrfb_request_ctx(struct vrfb *vrfb);
 extern void omap_vrfb_release_ctx(struct vrfb *vrfb);
 extern void omap_vrfb_adjust_size(u16 *width, u16 *height,
@@ -49,6 +50,7 @@
 extern void omap_vrfb_restore_context(void);
 
 #else
+static inline bool omap_vrfb_supported(void) { return false; }
 static inline int omap_vrfb_request_ctx(struct vrfb *vrfb) { return 0; }
 static inline void omap_vrfb_release_ctx(struct vrfb *vrfb) {}
 static inline void omap_vrfb_adjust_size(u16 *width, u16 *height,